If you’re considering building a new building, you may need to hire a concrete contractor. This type of contractor will have the skills and experience necessary to finish your project on time and within budget. You may be wondering whether it’s worth hiring a concrete contractor. You should be aware that a concrete contractor is responsible for providing you with a beautiful finished product and ensuring that it’s safe. While hiring a concrete contractor, you should consider their level of expertise and experience.

A competent concrete contractor will know the ins and outs of concrete construction and ensure that the finished project meets your requirements. If you’re unsure about the kind of work you need, you can check online reviews to get a feel for their level of competence and expertise. A contractor  should also work with different methods, including using stencils or stamps. While a great contractor will be able to do any of these tasks, you should make sure to find one that will match your budget.

In the case of decorative concrete, you can use the services of a professional to enhance your home’s decor and style. Whether you’re looking for a modern or traditional look, you can choose from a variety of textures, colors, and patterns. Using a concrete contractor will allow you to enjoy the results of your remodeling project without worrying about any foreseeable problems. In addition to this, your contractor will also help you with insurance questions.

Concrete is an essential part of any building and requires skilled, experienced contractors to ensure a great result. It’s a tough job, but it can also be rewarding. A concrete contractor can help you improve your home’s appeal. With a little help, you’ll be able to get a fantastic finish. There’s nothing better than knowing that you’ve made the best choice in the construction field. You’ll be happy you did.

As a concrete contractor, you should ensure that your project is done correctly. You should hire a concrete contractor that will meet your expectations. A good contractor will not rush into a new project. Rather, he or she will take the time to prepare the site. If you’re not comfortable with concrete, you should hire a concrete contractor with the expertise and experience necessary to finish your project successfully. It will make your construction more attractive to your clients.

While concrete contractors are essential for your project, you should also pay close attention to the edges of your forms. A concrete contractor should make sure that the base is leveled and that the concrete is leveled. A concrete contractor should also pay special attention to the edges of the foundation, since they affect how the cement will cure. If you’re using a concrete mixer, it is important to get an estimate of its costs and how much it will cost you.

There are several factors to consider before hiring a concrete contractor. First of all, they should be able to read blueprints. Secondly, they should be able to follow written instructions. Having a thorough knowledge of your local area will help you decide who will work best with your project. Additionally, they should have the patience and knowledge to properly manage a construction. And thirdly, they should be able to communicate well with the client.

If you’re considering hiring a concrete contractor, you should consider the type of project you want to build. If you’re planning to build a house, concrete contractors should be familiar with the specifications of the home you’re building. They should be able to explain how their projects will be constructed. Then, they should be able to answer any questions you may have. And the final step is to choose the best type of concrete for your project.

While the process of hiring a concrete contractor is essential, you should also keep in mind the importance of the decision. You should always choose the best contractor for your project. For example, you should never hire a contractor who lacks experience. A qualified concrete contractor will be able to meet the specific requirements of your project. A good one will be able to answer any questions you may have. The right contractors should have the experience and the knowledge to perform a great job.

Concrete Contractors can add significant value to a home aside from improving its look. It can also help you sell your house, which is good for the local economy. Many homeowners choose a concrete driveway for their homes. However, there are some differences between concrete driveways and pavers. For one, a concrete driveway has a flat surface. Secondly, it is more difficult to maintain. And, plain paper can easily become a mess. Finally, if you have a driveway that has to be repaved every few years, you may be forced to pay more money in the future.

Random cracking in a concrete driveway may not affect the long-term service, but it can detract from the appearance. For this reason, it’s best to choose a contractor who uses a uniform concrete mix. Alternatively, you can also use a vibratory compactor to ensure the surface is properly compacted. However, while a uniform mix is preferable, random cracks are still possible. For this reason, you should ask the contractor to provide you with information about their policies on this matter.

The concrete base must be uniform in firmness. Otherwise, it may become unstable when heavy loads are placed on it. A minimum slope of 1/4″ per foot is required to ensure proper drainage. The subgrade and base must also slope away from buildings and other structures. A six to twelve-inch base is ideal for optimal drainage and enhanced load capacity. When installing a concrete driveway, make sure the material is level and free of organic materials. It should also be flat and sloping away from home.

While it’s tempting to go for a square or rectangle driveway, the fact remains that concrete is the most sustainable option. It’s long-lasting, easy to maintain, and provides better heat resistance. It’s easy to install and maintain, and it can improve your curb appeal as well. Moreover, a concrete driveway is a great investment. If you’re looking for an environmentally-friendly material that is highly durable, consider a concrete driveway.

A concrete driveway contractor can use stenciled concrete to copy the look of brickwork and stone. It’s a good idea to discuss your preferences with a contractor before hiring them. Some concrete contractors offer a gallery of design templates to help you decide which material will look best on your property. If you want to add color and texture, you can use an embosser to create a pattern in the concrete. Incorporating embedded materials is another way to improve the appearance of a driveway.

A concrete driveway will not require much maintenance. The material will not stain or discolor easily. However, you will need to clean it once or twice a year. Then, if you’re a DIYer, you can pour the concrete driveway yourself. Just be sure to have the right tools and a crew that’s willing to help you. Then, the concrete will harden and become permanent. Afterward, you can use your decorative stamps to create a unique design for your home.

A concrete driveway is made of a mixture of sand, gravel, and other sand-sized particles. If you want a custom-made driveway, you can choose any pattern, color, and texture you want. In addition, you can choose a driveway that looks best with your house and landscaped yard. If you’d like your driveway to reflect light, you should consider the cost of concrete. But a customized patio can be costly.

The first step of installing a concrete driveway is to make sure the foundation is stable. In addition, you’ll need to remove vegetation to make sure the ground is level. A good way to do this is to lay class-5 gravel on the base of the driveway. Once the base is level, add the reinforcement material. Once it’s level, you’ll need to grade it. Then, you’ll need to lay the patio and a few rows of bricks.

Women in South Asia have long been doing intense physical labor in building sites and brick industries for relatively low pay. And, yet it is discouraging to be a part of a heavily male-dominated construction industry. Whenever I passed by a construction site, I felt powerless and afraid of the tools that men carried effortlessly, as if to prove that gender disparity in the labor market exists for a reason. In other words, the construction world felt unattainable in all its toughness.

Image Source: Women at work © The Record Nepal

As an aspiring architect, the dichotomy between architecture and construction seems nonsensical, particularly in the ever-evolving realm of sustainable architecture, where prototyping and experimenting are at the core of design processes. There is also an assumption that architects are above construction workers – a dynamic that sustains social and class imbalance. While there are many structures to criticize about, luckily, there are also associations like Critical Concrete who facilitate three-weeks of intense, hands-on workshops to understand the material, building techniques, and teamwork as part of the post-graduation course in sustainable architecture. The workshop positively shifted my perspective of the construction industry and further expanded my own personal boundaries.

“Let’s get our hands dirty!” architect Hanno Burtscher, instructed a team of ten women who came from different professional backgrounds, race, and geographical locations. Hanno introduced himself as an earthman, with an Austrian sense of humor, quick wit, and great teaching style, he grouped students in pairs to use all four senses except for sight to identify the local materials used for raw earth construction. This is how the welcome ceremony to the workshop began and it had already set a higher bar for the rest of the workshop. The joy of sharing stories moved the conversation from endless banter about cheese and food to serious topics like what sustainable construction means and how the uncertainty during the time of pandemic has affected our lives. In short, the day exuded a sense of togetherness. 

*Sketch by Charlotte Schneider, Alumni, Post Graduation 2020-2021

WEEK 1 | RAW EARTH CONSTRUCTION | HANNO BURTSCHER

The first week of the workshop was a battle – a battle to make proper earth mix to build a heated earthen bench and flooring for the kitchen at Critical Concrete. From the start, we learned that the key components of earth mix are clay, small gravel (0-5 mm), big gravel (5-15 mm), sand (0-4 mm), and water.

Most of us were already aware of the composition elements through our Raw Earth online course, but what made the difference in the practical workshop was the experimentation and improvisation in the mixing process since the excavation materials were available in limited amounts. The question constantly surfaced during the workshop – how do we make the most use of what is available around us? And this was a revelation in itself because theoretically, we learn the ratio – 40% of excavation, 20% of small gravel, 20% of big gravel, 20% of clay, and water – to achieve the desired mix. 

In practice, however, there had to be adjustments in the ratio based on the materials that were available to us. The way we integrated the composite materials together also made a big difference in the quality of the earth mix. So, at times we had to find creative ways of using what was available to us.

“While nearing the end of the earth mix for the floor, we ran out of the large size rocks. My typical mindset is to say, “Let’s just go buy more.” However, with the mindset of Critical Concrete to use what we already have, we were not going to buy more. To finish the mix, we scrounged throughout the construction yard looking for proper sized rocks and were able to get the right volume,” Mary shared her experience. And this was the general experience during the workshop – how to find sustainable solutions when we hit a roadblock.

In our earliest days of the workshop, we dropped a fist-sized earth mix balls from 1 meter height to see whether they stuck together or crumbled. We concluded that the ball should drop in larger pieces rather than completely shattering or sticking together. If it’s too sticky, either the clay or water content is too high which will result in a mixture that won’t be suitable to create a form. The same logic applies for the dry mixture as well. After a process of trial and error, we realized that there was no concrete recipe to achieve the perfect mix. But there were a number of factors that determined the quality of the mix. One of them is the clay content, which is normally 20 percent in total but depending on the situation, it could range from 5 – 30 percent. The purpose of the clay is to bind the materials but the more surface area we have in the mix, the more clay we require, from which we can derive that the smaller the surface area of excavation, the higher clay content would be required to bind it. Simple physics!

Many construction sites are not inviting spaces for women. Women’s work is often considered too frivolous to the degree that they are rendered valueless in the number-driven capitalist economic system. During the workshop, this dynamic was challenged. A team of mostly women and Hanno prepared the foundation for raw earth flooring and built the formwork for the bench. As I was lifting heavy stones and using power tools, I occupied a space that was not ‘normalized’ for women. I quickly realized that the problem wasn’t these too feminine, delicate hands but rather it was the devaluation of women’s work that put women in confinement of patriarchal ideas.

“We either put 100 percent into this or we don’t do it at all,” Hanno remarked while we were putting earth mix into the form work. The workshop was fueled by this exact mindset but was also filled with laughter and leisure in between our hard work. Overall, during the first week with Hanno, he guided us by observing the way we were interpreting the materials. We were able to experiment with the materials and make decisions based on our judgement.

Week 2 | Esposende Building Site | Hugo Dourado, Pietro

Degli Esposti, Martina Eandi

Esposende was roughly a forty-minute drive away from the city of Porto. And when the drive is long, conversations of past, present, and future start bouncing around.

“How do you say it?” Bara from Czech Republic asked.

“Vastu Shastra,” I repeated.

“And that means harmony of energy through design? That is how I would like to design the interior of my place one day,” remarked Charly from Germany. 

The conversation moved in such a way during the Esposende trip. The practical workshop as a part of the post graduation course merged people with similar ideologies, dreams, and passion of bringing social and political change through architecture and urban planning. The workshop also meant more than fulfilling a part of the course. Some of us had flown miles away leaving their usual life to come to Portugal to venture in a new journey.

*Sketch by Charlotte Schneider, Alumni, Post Graduation 2020-2021

The building site was under construction, so there were different tasks that the students could choose from such as fixing the board and batten cladding system, wood charring station, tiling the roof, or constructing a rocket stove.

The name rocket stove in itself made me curious. On top of that, I had also done some research on rocket stoves in one of the Participatory Design courses. I started my second week with Pietro, our Raw Earth course instructor and Martina, Mycelium course instructor, to complete the stove that could be used for both cooking and heating the entire house.

The making of the rocket stove involved lots of earth mix, it didn’t involve knowing rocket science at all. First, a stone wall had to be built to lay an exhaust pipe with an inclination of 30 degrees. The purpose of this was to carry the smoke from the rocket stove out of the house. For the stone wall, we prepared Argamassa (mortar) to attach stones of many sizes together and this alone took days to finish. As soon as the wall was completed, we started to make the exterior of the rocket stove with earth mix. The earth mix was ¼ part lime, 2 ½ part excavation, and ½ part straw. Since we were working with materials that were locally available, the excavation we were using included large stones. We wanted the mix to be a combination of lime, earth, and straw, so we sieved the stones out.

At times building with raw earth felt like cooking, in a sense that there is a process to achieve the result. You cannot skip a part to make the process faster, there is a procedure that you must follow otherwise the mix will not be suitable for construction. Therefore, while making the earth mix, it is important to completely let lime and excavation combine before putting any water. Once lime and excavation are completely mixed, giving off a grey-brown color, you slowly add water and straw to make a mixture. We used the cob technique to compress and compact fist sized balls, smashing it to attach them onto the pre-existing walls.

Slap slap slap!! We were hitting the earth mix on the side with a board to pack it down together. Another important thing that Pietro shared with us was that the cob technique allows us to build 30 cm per day. Since the earth mix is massive and wet, it needs time to dry and be compacted to build another layer on top of it. To keep the layers of earth mix interconnected, we created a vertebra-like structure at the end.

​​The rocket stove workshop made me realize how earth as a material is flexible. I could mold it in any shape I wanted and working on it with hands felt therapeutic. With the rocket stove, we were trying to achieve a dome shaped exterior to give it a character of its own. We molded the earth mix into long tiny sausages to create a curve on the upper part of the stove. It was interesting to see how earth could be shaped into any form with the right formwork which is also one of the big advantages of working with this natural material.

Life on Site

The Esposende building site was located between the ocean and mountains. In the early morning, you could see the tip of the mountains covered in fog and in the late afternoon during those early hot, summer days, you could see the blue ocean in the distance. With our cup of coffee that the Critical Concrete team prepared for us every morning, the day started with division of tasks and the students always got to pick first which task they wanted to be involved in.

After our coffee we all got into the groove and the site came to life again. Some of us were carrying heavy stones, using power tools, hanging on the roof putting tiles while others were listening carefully to what Hugo, our Vernacular Architecture course instructor, with immense knowledge and a sense of perfection, had to teach about board and batten cladding systems. It was fascinating to observe how everybody worked individually and in teams and clearly I wasn’t the only one who thought this. The neighbors in Esposende would walk by observing, commenting on our work, with their hands clasped behind their backs!

“It’s called umarell in Italian,” Linda shared jokingly.

Apparently, in Italian slang, umarell is when elderly people gather to observe construction sites and comment on how to do the work, often with holding their hands behind their back.

I became a umarell when it came to food. The Critical Concrete team prepared big batches of healthy, colorful vegan food during lunch time and we would all observe in awe. The variety of food made from simple ingredients that Critical Concrete provided us inspired me to be creative with food that we eat on a day-to-day basis. How many times do we actually think about eating in a sustainable manner? How do we creatively use leftover food in our diet? These questions among many others helped me unlearn and learn new ways of looking at sustainability.

Week 3 | Furniture Workshop | Samuel Kalika

I noticed how different building materials can be. Whereas with raw earth, exactness is not so important, with wood each millimeter is important. Building beautiful furniture requires many steps, patience, and exactness,” Viviana shared. After working with flexible material like earth, wood seemed like unlocking a whole different dimension. Samuel, our Participatory Design course instructor, understood this well and he made our work easier by giving us instructions on every powerful tool we were using.

Precision was the key. While cutting wood, if it’s 1 cm off, what could we do? We could not undo a cut once it was made neither could we adjust it, so a big part of the furniture workshop was to find a solution on the spot. We used many different tools to achieve the desired finish and construction: a universal machine to obtain desired thickness, sizes, flatness, and straight surfaces; the meter saw; the sander. Gradually the counters for the kitchen in Esposende house began to take shape. “As soon as I started approaching the work, I understood the importance of being precise in all the small details. Once we developed a good flow in the process, the work became easier and faster,” commented participant Linda Tonin.

*Sketch by Charlotte Schneider, Alumni, Post Graduation 2020-2021

While trying to achieve precision, mistakes are bound to occur but this is part of the learning process and that made the experience lighter and took away the fear of judgment. 

“To assemble the pieces, in particular for the bigger elements, we set up a strategy, naming the pieces of wood and measuring the different thicknesses needed for the joining beams. Since different people worked on the cutting process, sometimes the joints’ holes had different sizes. We took these mistakes as an occasion to add different colors of wood to fill the spaces: the mistakes, at the end, added aesthetic value to the furniture pieces,” Linda reflected.

REFLECTION

During the whole workshop, each one of us were sharing our experience of working in different environments. We were trying to understand what our preferences are, what materials, tools we like to use, and which instructors’ teaching style catered to our learning approach.

“Beyond the excitement, time passing and the verge to finish, it was necessary to maintain a safe working space, making sure you and everyone around is comfortable and don’t cause any danger. Having this in mind, I learned how to remain calm and careful with all the tasks, machines and my colleagues. This atmosphere brought a lot of awareness and future-thinking into my habits,” Agnieszka described her experience.

“Starting with the fact that the workshop took me out of all my comfort zones, I can say that the first learning was that the “unknown” can be very good. And the learnings went beyond practical. Being in contact with such an international and so human team certainly awakened in me my best version, my confidence in a more correct and viable future and made me reflect and work on my limiting standards. It was definitely a great achievement to be in a healthy work environment,” shared Júlia.

I resonate with both Agnieszka and Júlia. My experience with working in a group was liberating. It taught me how everybody in a team works differently — how each individual works, thinks, coordinates and cooperates while working on a project. On top of that, our group was very diverse, so learning from each one of them and getting to interact with everybody in-person felt special during this uncertain pandemic time. We were able to transfer our expertise and learn from each other’s skills. At the same time, we were a group of women doing construction work, realizing our own potential and that was empowerment in itself.

On a personal note, the workshop also altered my relationship with the construction industry and my perception of emancipated women. Historically, women have existed within the confinement of domestic space therefore women who occupy space outside of the predictable situations are labeled ‘modern’. And if the working conditions are healthy and their work is comparable to the status of a male, they are given recognition and visibility. But are all women able to get the same visibility and prestige as the emancipated, educated women? Women from lower class and caste in South Asia have been working in extreme conditions in construction sites and brick factories out of economic necessity. They have to go through daily work toxicity in a largely male-dominated workplace. While reflecting back on the practical workshop, I realize the utter importance of an equal workplace environment in the labor industry and greater recognition of those women who have paved the way.

The post An SSA student’s perspective on working in construction and practical workshops appeared first on Critical Concrete.

Did you miss our previous article…
https://concretedoctorsolutions.net/?p=240

Where would we be without concrete? It’s one of the most versatile and essential products for almost all construction projects across the world. It’s a substance that fills our world and can be seen in almost everything we see, but also one that is so easily overlooked.

There are so many uses for concrete. Its applications and uses are more varied and more widespread than you can imagine. There are over 20 different types of concrete that are used in a multitude of construction projects, but what are the most popular applications for it? What is it that makes concrete such an advantageous material to use, and how is it used in both domestic and commercial developments. Let’s take a look.

Origins of Concrete

Concrete, in one form or another, has been with us since 6500 BC. It can be traced back to what is now, the United Arab Emirates, where Nabataea traders created concrete floors, houses and even underground cisterns.

The Egyptians were using it to build the pyramids in 3000 BC, where they used mortars of lime and gypsum to create their version of cement. It was also used, not surprisingly perhaps, to help construct the Great Wall of China. It didn’t become concrete, at least what we recognise it as today, until the 1800s, but since then, its uses have grown more and more.

Buildings

For any of us living in a house or working in a building, it’s likely to be made from brick and mortar to some degree. In the UK, it took off after World War II as part of the rebuilding efforts. Nowadays, it’s probably the most popular application of concrete in the modern age and will be for centuries to come.

Foundation

Even if the building itself is more steel and glass, its foundations will be made from or secured in, concrete. Concrete is so popular because it won’t burn or rot, which means that the foundation is going to maintain its strength and rigidity for many years.

Roads and Bridges

As we move up in the world, the very streets you walk on and the bridges you use to cross those roads will also be made of concrete. Again, concrete wins against other materials because of its durability and safety. It might not be obvious, but another advantage of concrete in these environments is that it offers better reflectivity at night. Of course, it’s not just pedestrians it has to support, but because it can hold heavier weights, such as cars and trucks, it’s the perfect material to use.

Why Concrete has so Many Uses

The applications for concrete don’t stop there. They are only the start. Concrete is so popular in different projects simply because of its adaptability. It’s not sensitive to moisture, can be shaped and moulded into almost any design, affordable and is recyclable.

It has a very long lifespan, doesn’t release any dangerous organic compounds and is just as safe for inhabitants. It’s easy to forget the difference concrete has made to our world, but just look around and you’ll see that it’s everywhere.

Contact Us

Thank you for reading this blog post. Should you be looking for any mixes or perhaps ready mixed concrete itself, then we can deliver it straight to your door. So, if you have any upcoming tasks, then get in touch today on 01442 389105 or visit our contact page for more details.

The post The Many Uses of Concrete first appeared on Base Concrete.

How To Seal A Concrete Floor?

Using concrete flooring in your home can be an excellent choice. Especially if you’re interested in the durability of your floor. However, to make a concrete floor last it’s important to seal it properly since concrete is porous.

Sealing a concrete floor is an effective way to keep your floor free of stains from substances such as grease, oil, water, and others. As if that’s not enough, sealed floors look beautiful and are easier to clean.

To ensure that the sealer is effective, however, the application process has to be done properly. Everything you do, from surface preparation to picking the right application tool, will go a long way towards determining the final outcome. 

How To Go About Sealing A Concrete Floor 

Here’s a quick summary of what you should do when sealing a concrete floor

Clean the floor (remove stains, dust, oil, etc. from the concrete)  Remove any old sealer from the floor Use an etching solution to open up the concrete Use a sprayer or roller to apply the first thin coat of sealer  After the first layer has dried, apply a second coat of sealer in the opposite direction Leave the sealer on the concrete until it dries fully (avoid driving or walking on the concrete until it’s dry) 

Cleaning the floor

To avoid inconvenience, you should remove the furniture and everything else from the room. Keep in mind that you will need somewhere to store the items for no less than one week. Once the room is clear, sweep it thoroughly, and then proceed to clean any area that is still dirty. 

You can use mineral spirits to clean grease spills. Once the floor looks clean, use a concrete cleaner to ready the floor for sealing. Rinse the cleaner off, and then wait for the floor to dry. At this point, you can use a concrete repair caulk to fill any visible cracks. Then finally, wait until the caulking has dried completely.

Removing the old sealer

If the floor had an old sealant, you have to wait before applying the new sealant. If you’re not sure whether a sealant was used on your floor or not, you can use water to test this. To do this pour approximately one cup of water on the concrete.

If the water does not soak into the floor but instead beads up and remains on the surface, the floor had been sealed. If the floor had not been sealed, the water would soak into the floor. To remove the sealant, you can use a chemical stripper.

Since chemical strippers are acid-based, be sure to protect yourself when removing the sealant. After removing the sealant, you’ll have to let the floor dry for at least 24 hours before proceeding.

Choosing the sealer

There are four main types of sealers to choose from:

•   Acrylic sealers 

This kind of sealer sits on top of the floor and is mainly used to seal interior floors. Acrylic sealers are easy to apply, but they don’t protect the floor effectively against grease and oil stains when compared to other sealers.

•   Epoxy sealers 

Despite being more durable compared to acrylic sealers, this type of sealer also sits on top of the concrete. Epoxy sealers protect your floor effectively against grease stains, but they are difficult to apply. They are also available in various colors enabling you to change the look of your floor.

•   Polyurethane sealers 

This type is mainly meant for use over other types of sealers. Polyurethane sealers have UV protection, which keeps them from turning yellow over time. They also sit on top of the concrete, but the layer is usually thinner.

For this reason, polyurethane sealers are mainly applied over epoxy as the top layer. The sealers are available in semi-gloss, matte, and glossy finishes. Such sealers are typically fine when used over other sealers, but if you’re not sure, you can always get some clarification from the shop you are buying from.

•   Silane/siloxane sealers 

You can use this type of sealer if you don’t want to change the look of your floor. Since the sealers penetrate the concrete, it won’t become glossy or darker. It will retain the matte grey color. This kind of sealer lasts 20 years or more and is effective in protecting the floor against stains and deterioration.

pplying the sealant

Here’s what you should do when applying the sealant:

1. Carefully read and understand the instructions

Every sealant is a tad different from the other. For that reason, you should read the manufacturer’s instructions to attain quality results for your project. Be sure to pay attention to important details such as the most appropriate temperature and humidity recommendations for application.

2. Ventilate the room

In whatever room you’re working from, ensure that there is enough ventilation by opening the windows and doors where applicable. You can also use an outside-facing fan to facilitate the movement of air from the room to the outside area.

3. If using an epoxy sealant, mix the two parts together

Epoxy sealants come in two different containers whose content should be mixed before application. In such a case, you should pour the content of the smaller container into the bigger one and then use a stir stick to mix them thoroughly.

You should mix them only if you’re ready to start the application process. It’s also important to note that you’ll have a period of one hour or so to get the epoxy down. For that reason, you have to be quick when working.

4. Divide the room into smaller sections 

It’s recommended that you divide the room into four sections for ease of application. You should start with the least accessible section, and work your way out to the door so that you won’t have to walk on the wet sealant.

5. Use a small paintbrush when sealing the edges of the floor

Get a paintbrush that is 5.1 to 7.6 cm wides and use it to apply the sealer along the edges of the concrete floor where the paint pad or rolling brush may not reach. Be sure to use nice, even strokes when applying the sealer.

6. Apply the sealer using a rolling brush or paint pad 

Pour some sealant into a painting tray and then dip a roller brush or a paint pad into the paint. If using a roller brush, be sure to roll the brush evenly in the paint. Use the roller brush or paint pad to apply a thin coat of the sealer along the edge that you’ve already painted.

Continue applying the sealer across the floor until you’ve covered the entire floor. When applying the sealer, you should ensure that there is always a wet edge to carry on from. The reason for doing so is to achieve a uniform look on the floor. 

Since you’ve already divided the room into smaller sections, you can work on each one of them at its own time. As you apply the sealer, make sure that you spread it evenly across the floor. You should also keep track of your area of coverage to avoid ending up with some patches that haven’t been sealed.

7. Apply a second coat 

For a smooth and even finish, you should apply a second thin coat. To ensure better coverage of the sealant across the floor, you should apply the second coat at right angles to the first one. Let the sealer dry as per the time recommended by the manufacturer on the sealant can, before walking or driving on the concrete. You should be ready to wait for up to four days to allow the sealant to dry completely.

Final thought, 

Sealing your concrete floors is a foolproof way to increase their lifespan while also enhancing their beauty. The good thing is that you can easily complete a floor sealing project by yourself. If, however, you’re not particularly confident with your DIY skills, you should hire an expert.

If any of our high-quality services interest you, give us a call on 01442 389105 or 07812 182778 today. Or fill out the enquiry form on our contact page for more information.

The post Top Tips To Sealing A Concrete Floor first appeared on Base Concrete.

If you are interested in our kimchi making process, click here to skip to the section about kimchi directly.

Do you ever stop to think about how you’re able to enjoy fresh strawberries, blueberries, and peaches in Winter? Contemporary food systems make an enormous variety of food available at any time of year. Produce travels long distances to be sold where it isn’t in season, undermining the business of small farms and emitting greenhouse gases. Local foods are riper at harvest because of shorter travel times, and choosing to buy local also supports the local economy. But even while shopping local, unseasonal food can be harmful to the environment; energy-intensive food production methods like greenhouses can produce 3-10 times the emissions as imported foods.[1]

Understanding why our food goes bad and what accelerates its decay helps reduce food waste, but fridges are only good at storing fresh produce for relatively short periods. There is a wide range of alternatives to fridge storage that keep fruits and vegetables from rotting for months or even years. This article will detail some long-term storage methods and their benefits depending on region and culinary purposes, and we will take you through our process of fermenting cabbage for kimchi.

When you decide to cut down the carbon emissions of your food, the produce available to you changes seasonally. The good news is that there are ways to store these foods for long periods so that you can still eat and cook with foods after their peak seasons. Alternatives to refrigerating food have existed throughout history, but the availability and convenience of the fridge has brought some of these practices out of the mainstream.

The two categories of traditional, low-tech food preservation are storing food in containers that control temperature and humidity, or preparing food to slow down its decay. 

Storage Methods for Food Preservation

It is important to note that food storage differs in summer and winter because different variables cause food decay in each season. Traditional food storage containers address the needs of produce through passive strategies that make use of the climate.

Zeer Pot

In hot and dry climates, natural fridges make use of evaporative cooling on the outer surface of a clay pot. In this method known as the Zeer Pot, water evaporation converts sensible heat to latent heat. This means that energy is released when liquid water is converted to vapor, reducing the temperature inside the container. The method uses two clay pots, one inside of the other. Between the pots is a layer of sand into which water is poured to begin the evaporative cooling process. Evaporation is continuous, ensuring that the natural fridge stays cool all day, but it relies on an outside temperature hot and dry enough to cause evaporation. Because the Zeer Pot serves the function of a fridge, it does not extend the life of food or preserve it any longer than a fridge, but it is necessary to mention when discussing how to store food without refrigerators or freezers. 

Root clamp using upcycled container

In cool climates and during the Winter months, some vegetables can stay fresh for longer by taking advantage of a steady temperature underground. Root vegetables can avoid frost by being buried, as ground temperatures fluctuate significantly less per day and can stay warmer than the winter air temperature.

Burying vegetables (and some fruits) can be done through covering the planted vegetables with soil or straw, or through harvesting the vegetables and putting them in small underground holes called clamps or silos.[2] Underground food cellars, when available, serve the same purpose. Given that a majority of the world population lives in urban areas, the first option is not as accessible, as it relies on growing your own food in large quantities. The last option, an underground root cellar, is useful for larger quantities of foods and can also be used to extend the shelf life of more than just fruits and vegetables.

Root Cellar

The most accessible of the three ways of burying vegetables is the “clamp” or pits that are completely or partially buried. These can be built relatively quickly using very little garden space and can upcycle used household items (such as washers or steamers). Proper care must be taken to ventilate to avoid mold and to protect the food from rodents or other pests. For protection against rodents, the trench can be lined with rust-resistant metal mesh, which simultaneously aids ventilation. Another method to strengthen ventilation is to place a bundle of twigs in the center of the pit to act as an air shaft. The old drums of washing machines are perforated, which makes them perfect pest protection, but bricks can also be used for the walls and ground of the pit as well. To protect against rain, a plastic sheet can be used to cover the pit, although there may be a problem if the soil around the vegetables becomes extremely saturated from heavy rainfall. 

Root Clamp

Sand storage is helpful to use in tandem with other cold storage methods because it regulates moisture conditions. It can be done at multiple scales, so in large boxes in a root cellar, in a root clamp or food pit, or even at the bottom of your fridge drawer, and it works with all root vegetables, onions, leeks, shallots, and cauliflower.[3] Sand storage entails pouring sand into a container and then submerging the vegetables completely.[4] The sand serves the purpose of a humidity regulator, removing excess moisture, so vegetables cannot be washed before they are stored in this way.[5] Sand storage requires that there be space for ventilation between the vegetables being stored, and the sand container should stay out of heated rooms or areas that are below freezing.[6] If you do not have a food pit, cellar, or food clamp, you can use this method on its own if you have a cold enough garage or, as mentioned above, in the bottom of your fridge drawer.[7]

Preservation Through Food Preparation

Drying

Drying food using a dehydrator, an oven, and the sun

Drying is a method best used for fruit, mushrooms and herbs. It is more easily done during summer because there is more heat and more fruit available to dry, but in the winter, citrus and fungi can be dried in the oven which helps heat the house. Vegetables can also be dried, but they should be blanched, or boiled quickly, before drying, which removes some healthy enzymes.[8] Dried foods retain most of their vitamins, except vitamin C, which degrades quickly.

Foods can be dried in the sun, in an oven, or in a dehydrator, making sure to allow sufficient space for ventilation. The process of drying takes several hours, but it is very hands-off, as most of the work involved is preparing the food by slicing it and putting it on drying trays. When using the oven, care should be taken to set a low enough temperature to avoid burning. Dried fruit is a delicious snack and can be added to baked goods for its flavor and texture. Mushrooms and herbs are multipurpose when dried, and just like dried herbs, mushrooms can be ground to produce a delicious seasoning powder for any meal.

Fermenting

Fermented foods preserve well because the acidic environment blocks bacteria from multiplying. Lactic fermentation is the process in which lactic microbial organisms convert sugars into lactic acid, creating an acidic environment that inhibits bacterial growth.[9] It is best known for making sauerkraut and other cabbage dishes, like kimchi and Salvadorian curtido. Usually the process is to cut vegetables, season them, and leave them in their own juices to ferment for a few days or a few weeks. Then, jars are stored in a cool place—either in a cellar or fridge—and last a year or more. At room temperature, sauerkraut lasts up to a few months,[10] but kimchi will only last about a week if left out.[11] Lactic fermentation allows more raw vegetables to be eaten throughout the year without relying on food travelling long distances. When eaten uncooked, fermented foods preserve their enzyme and vitamin content while adding healthy probiotics.[12] Fermentation adds acidity and a distinct fermented flavor.[13]

Canning and Salting

Canning relies on heat to kill both bacteria and enzymes.[14] Canned food is prepared by placing food in sterilized jars, then boiling the closed jars of food for several minutes to stop factors that cause decay, so the food stays edible almost indefinitely.[15] Canning is an easy process that is helpful for storing foods that will be cooked anyway. However, if we relied on canning to preserve all our food, we would miss out on beneficial enzymes and vitamins.

Salting protects food from the multiplication of bacteria because salt draws the moisture out, creating an inhospitable environment.[16] Often, salted food is rinsed before it is used for cooking, which reduces the sodium but, unfortunately, removes some of the nutritional value from water-soluble vitamins.[17] To work around this disadvantage, salting is best used if the preserved food is intended to be cooked with a high amount of salt, such as in broth, or simply consumed in small quantities.[18]

Our Approach

Every method for storing food in the long-term has specific conditions for which it is ideal. At Critical Concrete, we implemented some of these strategies according to the conditions in Porto.

Local climate is a necessary component of food storage strategies. In the case of Zeer Pots, low humidity is essential to ensure evaporation. As Porto is relatively humid even in the summer, evaporative fridges are not appropriate for keeping food cool in this area. On the other hand, burying produce is optimal in a cool and dry climate.[19] It can even be effective in places that receive snow, as long as certain precautions are taken against moisture.[20] Food preparation for preservation often lasts six months or more. Fermented foods last longer when stored away from sunlight and direct heat, while dried foods need to be stored in a dry environment, such as in dry bags or jars.

Pouring water in the sand layer of our natural fridge to trigger evaporation

In the Summer of 2019 we attempted to build a natural fridge. However, the temperatures inside were not cold enough to store food; on the hottest day, the fridge was 17 degrees, and on cooler days the temperature inside was 13 at the lowest. This is quite logical given Porto’s humid climate, which resulted in less evaporation, and on the warmest day we recorded temperatures, it was only 21 degrees outside. Our unfortunate results emphasize the need for attention to specific climate in storage methods for food preservation.

Kimchi

To look into food preparation methods for long-term storage, we attempted lactic fermentation, using a recipe for vegan kimchi available on the blog Maangchi.com.

We compressed it into the jars to avoid air bubbles. After 5 days fermenting at room temperature, we placed the delicious kimchi in the fridge. (Normally, fermentation at room temperature only occurs for 1-2 days, but we stored it in a very cold unheated room.)

In these before and after images, we can see the evidence of fermentation: there are dozens of air bubbles where, prior to fermentation, we could only see a few. The difference in hue is only due to the artificial lighting used in the first image, however the cabbage is slightly more translucent after fermentation.

Our kimchi turned out wonderfully, but we noticed a few things in the process of making it. First is that it is not shelf stable, relying on the refrigerator to extend the lifetime past a week. (When we build a cool cellar in the Critical Concrete kitchen, the kimchi can be moved there to limit reliance on the fridge.) Secondly, when getting the cabbage ready to ferment, we noticed that the wider jar made it easier (than two other small jars we filled) to pack kimchi without allowing bubbles. Third of all, though slightly minor, is that when preparing kimchi, it is necessary to soak cabbage in brine and then rinse several times to remove the salt. This has the same caveat as preserving food with salt: losing water-soluble nutrients from rinsing. That being said, kimchi makes up for any lost nutrients in probiotics and flavor, and can last more than a year when stored correctly.

Conclusion

When used in the relatively humid summers of Porto, the Zeer Pot technique offered little relief from the hot outside temperatures. In drier climates, it could be a simple and low tech way to expand cold storage or, even better when possible, reduce the need for a fridge. During the winter, burying food is a great way to extend the life of vegetables, although, as mentioned, the reality of urban living makes it difficult to accomplish in many homes. If it is an option, there are many traditional ways to go about it, but each one needs to carefully protect against moisture, cold, and pests.

Salting and canning are two simple methods of food preservation that are perfect for certain dishes, but both affect the nutrient content of food significantly. Dried food offers a wide variety of purposes: in baked goods, as snacks, or as seasoning. As most homes have an oven, it is quite accessible. During the summer it is more energy efficient, but, on the other hand, can help heat your home in winter. The process of fermenting requires very little energy expenditure and can be used for a wide variety of produce, but it is especially suited for vegetables. In fact, as drying can be better for fruits and fungi, and fermenting is great for vegetables, these two methods of preservation complement each other. Although fermentation alters the flavor of raw foods, this can be a benefit. In the case of our homemade kimchi, fermentation was a success. However, it failed to reduce our reliance on the fridge, while still posing some of the problems of salt-preserved food.

Our food culture is built around having every variety of food available constantly, without inspiring consumers to consider where and how that food is produced. There are often significant challenges to eating local, seasonal food, and, at the same time, it won’t solve the world’s problems to only eat such food. However, eating seasonal food when possible leads to more delicious, nutritious meals and helps the environment simultaneously. 

Stay tuned for our next food article in the series, on the use of food scraps.

Sources

[1] Ritchie, Hannah. “You Want to Reduce the Carbon Footprint of Your Food? Focus on What You Eat, Not Whether Your Food Is Local.” Our World in Data, Global Change Data Lab, 24 Jan. 2020, ourworldindata.org/food-choice-vs-eating-local. 

[2] Preserving Food without Freezing or Canning: Traditional Techniques Using Salt, Oil, Sugar, Alcohol, Vinegar, Drying, Cold Storage, and Lactic Fermentation. Chelsea Green Pub., 2007. 

[3] https://www.gardeningknowhow.com/edible/vegetables/vgen/storing-root-crops-in-sand.htm#:~:text=Root%20veggies%20that%20grow%20vertically,to%20entombing%20them%20in%20sand. accessed 18 February, 2021.

[4] https://www.gardeningknowhow.com/edible/vegetables/vgen/storing-root-crops-in-sand.htm#:~:text=Root%20veggies%20that%20grow%20vertically,to%20entombing%20them%20in%20sand. accessed 18 February, 2021.

[5] https://www.gardeningknowhow.com/edible/vegetables/vgen/storing-root-crops-in-sand.htm#:~:text=Root%20veggies%20that%20grow%20vertically,to%20entombing%20them%20in%20sand. accessed 18 February, 2021.

[6] https://www.gardeningknowhow.com/edible/vegetables/vgen/storing-root-crops-in-sand.htm#:~:text=Root%20veggies%20that%20grow%20vertically,to%20entombing%20them%20in%20sand. accessed 18 February, 2021.

[7] https://www.gardeningknowhow.com/edible/vegetables/vgen/storing-root-crops-in-sand.htm#:~:text=Root%20veggies%20that%20grow%20vertically,to%20entombing%20them%20in%20sand. accessed 18 February, 2021.

[8] Preserving Food without Freezing or Canning: Traditional Techniques Using Salt, Oil, Sugar, Alcohol, Vinegar, Drying, Cold Storage, and Lactic Fermentation. Chelsea Green Pub., 2007. 

[9] Preserving Food without Freezing or Canning: Traditional Techniques Using Salt, Oil, Sugar, Alcohol, Vinegar, Drying, Cold Storage, and Lactic Fermentation. Chelsea Green Pub., 2007. 

[10] https://growyourpantry.com/blogs/fermenting-pickling-preserving/how-long-does-sauerkraut-last, accessed 18/01/21.

[11] https://www.healthline.com/nutrition/does-kimchi-go-bad#shelf-life, accessed 18/01/21.

[12]Preserving Food without Freezing or Canning: Traditional Techniques Using Salt, Oil, Sugar, Alcohol, Vinegar, Drying, Cold Storage, and Lactic Fermentation. Chelsea Green Pub., 2007. 

[13] Preserving Food without Freezing or Canning: Traditional Techniques Using Salt, Oil, Sugar, Alcohol, Vinegar, Drying, Cold Storage, and Lactic Fermentation. Chelsea Green Pub., 2007. 

[14] Seymour, John. The Self-Sufficient Gardener: A Complete Guide to Growing and Preserving All Your Own Food. Dolphin, 1980. 

[15] Seymour, John. The Self-Sufficient Gardener: A Complete Guide to Growing and Preserving All Your Own Food. Dolphin, 1980. 

[16] Preserving Food without Freezing or Canning: Traditional Techniques Using Salt, Oil, Sugar, Alcohol, Vinegar, Drying, Cold Storage, and Lactic Fermentation. Chelsea Green Pub., 2007. 

[17] Preserving Food without Freezing or Canning: Traditional Techniques Using Salt, Oil, Sugar, Alcohol, Vinegar, Drying, Cold Storage, and Lactic Fermentation. Chelsea Green Pub., 2007. 

[18] Preserving Food without Freezing or Canning: Traditional Techniques Using Salt, Oil, Sugar, Alcohol, Vinegar, Drying, Cold Storage, and Lactic Fermentation. Chelsea Green Pub., 2007. 

[19] Preserving Food without Freezing or Canning: Traditional Techniques Using Salt, Oil, Sugar, Alcohol, Vinegar, Drying, Cold Storage, and Lactic Fermentation. Chelsea Green Pub., 2007. 

[20] Preserving Food without Freezing or Canning: Traditional Techniques Using Salt, Oil, Sugar, Alcohol, Vinegar, Drying, Cold Storage, and Lactic Fermentation. Chelsea Green Pub., 2007. 

The post Knowing our Food: Preservation first appeared on Critical Concrete.

Index

IntroductionOur researchWhy cellulose based insulation?Why lime instead of cement?Cardboard+lime insulationMaking and applyingConclusions and further steps

Introduction

In recent decades, we have seen many examples of individuals and collectives striving for a greener way of building: reviving traditional methods, favouring natural materials or including recycled elements in the process to limit the footprint. Critical Concrete embraced this aim from the beginning: in 2017, we started experimenting with cardboard based insulation, and since then we have been working with other materials (such as wool or mycelium) that can serve as valid alternatives to the more polluting conventional ones.

This article presents our journey and experience researching and developing prototypes for cardboard-lime based insulation. We will talk about why we decided to dig deep in lime and cellulose based materials, and what we learnt from our prototyping. Our research aims to deepen the recycled paper and cardboard potential as top sustainable insulation material.

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Our research

More expensive rents means more people having to live in precarious houses1. Housing poverty is one of the leading global issues2, affecting more and more people in the face of climate change. The lack of thermal comfort causes serious health issues, and is responsible for many preventable deaths especially among vulnerable and low-income communities.

In Portugal, where we are based:

Almost 20% of people claimed to be unable to keep their home adequately warm during winter.335.7% said their house is not comfortable during summer.4In 2018, at least 1 in 5 people lived in a dwelling with a leaking roof, damp walls, floors or foundation, or rotting window frames or floor.5

Our priority is to improve housing conditions through affordable and environmentally friendly solutions. This is the main reason our research lab has been focusing on insulation methods for many years.

We started experimenting with cardboard in 2017 due to the high performance of cellulose insulation. Our research began considering the advantages and handicaps of using corrugated cardboard as an insulation panel. So far, we produced boxes and panels for a low-tech insulation system and applied it in different summer school houses, in cases the insulation could not be applied on the exterior of the house (houses in line, no space in the street, etc.).

Last  year, we decided to move forward in our research and try to find a method to continue producing cellulose based insulation but on a larger scale, since we wanted to continue developing an insulation that would be mineral-based and would not need to be covered by a plywood board or equivalent.

Why cellulose based insulation?

Cellulose is the organic compound mainly used to produce paper and cardboard, and other wide varieties of derivative products. It works as a very competitive insulation material, “depending on manu- facturing and method of installation and is comparable with other types of insulation. It has an average thermal conductivity being of about 0.040W/mK (similar to glass wool and rock wool insulations)”.6

Paper and cardboard are extensively used and abundant resource. Reusing and recycling cardboard locally7 also reduces emissions substantially:

In 2016, 50 660 000 tons of paper and cardboard wastage were produced in the European Union. Almost one million (905 137 tons) just in Portugal.8That year, within the EU, 72% of that waste was recycled. Whilst in Portugal the percentage was 55%.9

This means that we may take advantage of a material with high insulation performance and avoid it to become disposal waste at the same time, adding a new step in its life cycle.

There are many examples of people working with cellulose based materials, as the known papercrete, which since the ‘90s has been used in informal bio-constructions around the world. Papercrete is the building material made of paper pulp and cement. The main advantage of it is “that it is lightweight but sturdy enough to bear loads10. But we didn’t want to use cement.

Why lime instead of cement?

Cement became especially relevant during the industrial revolution and it has changed our way of building from that moment. Nowadays, as an affordable and easily accessible material, cement might seem like the perfect solution to achieve efficient results quickly. However, the environmental impacts of the material are very concerning.
The most well known fact is the excessive CO2 emission of the cement industry, as it occupies 3rd place of global CO2 emissions11. But even if emissions dropped gradually with innovation efforts to create the green concrete12, we are not sure if the industry will ever be fully sustainable and carbon-neutral.

Why? Because the environmental harm does not stop with CO2 emission. We have to keep in mind:

other additives in the material’s production,excessive water usage (both during cement production and construction with concrete), centralized production, lack of perspirability of cement forces the combination with other unbreathable, synthetic materials.complexity/impossibility of recycling concrete, often reinforced, combined with lightweight materials, or in complexe composite materials,that concrete surfaces trap heat and prevent rainwater absorption,

That makes cement the ultimate enemy in sustainable architecture. It is time to opt for alternatives. To reduce our environmental impact, we put our votes to use lime: in contrast to cement, lime is biodegradable and fully-recyclable (even on bricks), and most of the time, locally produced.

A more detailed article on cement will be published in the upcoming weeks, stay tuned!

Cardboard+lime insulation

Key concepts

Cardboard pulp: Cardboard soaked in water for at least 12 hours, and then squeezed and mixed with an electric mixerCardboard+lime paste: The whole mix we used for our prototypes. Its composition changed over time as described below.Quicklime: Calcium Oxide. CaO. The outcome of heating limestone. Slaked lime: Hydrated lime. Ca(OH)2. It is the paste result of putting enough water so that the quicklime combines chemically with it.Natural hydraulic lime: Ca(OH)2+reactives. It is used to make mortar which sets through hydration.

Since this last year, we have been working on what we call cardboard+lime, based on papercrete in which we swapped cement with lime. Our goal of producing insulation allows us to use a non-structural, but less harmful material. In the first experiment, we mixed lime and cardboard14 in a small brick shape which looked very promising in terms of resistance. We were really curious about what we could get from there.

The first question that appeared was which shape should we give to these prototypes: Should we continue with bricks? Should we try with panels? In our previous research, the amount of time that producing panels takes was one of the biggest handicaps, so we decided to look for a way to remove this step from the process. We opted for making shuttering molds and applying a cardboard+lime paste in situ.

First prototypes

We have made many prototypes, have learnt different new things from each one and have tried to improve in each new attempt. The second cardboard+lime paste was made from recycled cardboard that we got from Lipor, water, sand and natural hydraulic lime (NHL) and was applied in a temporary wooden formwork of 1 m2 and 8 cm of thickness.

Recipe and setting process

We started with a basic mix made of (proportion in volume):

Cardboard15 pulp70%Sand 20%NHL 5 1610%

That first trial gave us an overview about the outcome we wanted to have and what was missing. In the following prototypes, we added borax for added resistance to fungi and mould. We also increased the proportion of hydraulic lime, reducing the sand; this made the mix easier to mix and apply. We got a better consistency in the cardboard+lime paste and we could notice it during the curing: the prototype was more compact and homogeneous.

Over time, we saw a small shrinkage up to 2% of their sizes and the terrible appearance of mould on the second and third prototypes. The cardboard+lime paste shrinks because of the amount of cardboard pulp –it tends to shrink when it loses its water– in the final mix; and the mould appears because of the slow setting process.

How did we try to solve this?

Adding slaked lime in order to kill any kind of life that wanted to appear.Adding plaster to accelerate the curing process.Reducing the percentage of cardboard pulp.

Thus, our final cardboard+lime recipe got its shape (proportion in volume):

Cardboard pulp62%Sand15.5%NHL 515.5%Slaked lime2.3%Plaster2.3%Borax2.3%

Shuttering and structure

In the beginning, the shuttering was thought of as a temporary structure –such as those we can see for making concrete– compound of vertical wooden pillars and boards. After the first prototype, we realised this was not feasible if we wanted the cardboard+lime to be a solid and permanent insulation attached to the wall.

In order to achieve a safe insulation that could last for years in place, we designed an internal structure secured to the vertical one and the wall in such a way that only the boards were removable. At the end, we decided to also add interior beams to completely ensure the cardboard+lime insulation.

Making and applying cardboard+lime

As the recipe and the structure evolved over time, so did the production process.. With the addition of new structural elements, such as the inner string and beams, the procedure became more complex.

We had to follow a step by step process in which the use of one tool or another could save us a lot of time, as well as the outcome could change completely if it was not followed properly. Furthermore, the setting process could be slashed depending on the context: are we working during Summer? Are we working in a humid zone? Do we have enough ventilation? And with it, the properties of the insulation.

How to make the cardboard+lime insulation

Disclaimer: Calculation for 1 m2 insulation. First, measure the whole wall you want to insulate and divide it in the best way it can fit. Also, if you are making the insulation in a stone/concrete wall, mark and make all the holes you will need.

Cardboard+lime paste – with the proportion referred before

For making the cardboard+lime paste we need to first prepare the cardboard pulp and the slaked lime (you can buy ready-made lime putty, but we used to make it ourselves).

Slaked lime

This is a dangerous chemical reaction, so we advise to use goggles, mask and gloves.

In a large metal container –nothing plastic though, as the heat generated by the reaction will melt it–, add one part quicklime to three parts water.Always add quicklime to water, and never water to quicklime, as it will spit, and can be very dangerous.The reaction should start and it can achieve temperatures over 100ºC.Wait until cooled down. Usually we prepared the mix at least one day in advance.

Cardboard pulp

For 1 m2 of cardboard+lime insulation, 6 cm thicker, you will need 65 l of cardboard pulp.

Tear/shred the cardboard into 4-5 cm pieces and drop them into a bucket until almost full.Pour enough water into the bucket to soak the cardboard pieces.Let the paper soak for at least 12h (and no more than 48).Attach the mixer to the drill and move it around in the cardboard to shred it to a pulp.Squeeze and reserve.

After having these two ingredients ready, we can start the mix!

In a concrete mixer, put half of the cardboard pulp, the hydraulic lime, the sand, plaster, borax and the slaked lime.Start the machine and add the rest of the cardboard pulp little by little to get a better mix.If you see the mix becoming small balls, stop and tear them apart. Mix again until having an homogenous mix.

Applying the cardboard+lime paste

For the shuttering we use 6×6 cm wooden bars and 100×33 cm plywood boards.

Make the frame where the shuttering will be placed. Mark where the structure is going to be placed. Place a bar horizontally on the floor (a), attach it to the wall with screws. Place two bars vertically (b) with 1 m separation between them. Measure from the axis of each bar. Attach them to the wall with screws.Put four screws (c) drawing a ‘z’, two of them on the vertical bars with ~20 cm distance and the other two on the wall at the same high. Tie a string (d) ]to the first screw – the one closer to the horizontal beam on the floor–.Stretch the string to the next screw –the one at the same high that the one before–. Don’t tie the string because we will need to tight it later.

Screw the wooden board to the pillars.Start pouring the cardboard+lime paste until it covers the string. Press the paste.Tight the string.Pour more cardboard+lime paste.Stretch the string to the third screw, in diagonal.Pour more paste. Press it. – The more you press, the better.Tight the string, stretch it to the last screw on the pillar. Put a beam with nails (e) small beam]. Press.Repeat from point 2.

Setting process

Remove the boards after 3 days. There is no risk of downfall, but the cardboard+lime paste is still wet so be careful not to beat it. The setting process can last for many weeks until the insulation is completely dry, but with the proper conditions it should be around 3 weeks. During these three weeks the insulated room must be well ventilated – cross ventilation is always the best- to avoid the condensation and with it, the slowed down of the curing process.

Conclusions and further steps

After almost one year of researching and observing the behaviour of the different prototypes, it seems fair to say that cardboard+lime, with the recipe shown above, is indeed proven to be a promising insulation material.

But we ended on a process that is a bit crazy. We realized that applying cardboard+lime as we did needs specific conditions and a meticulous procedure. So, yes, for experienced building people cardboard+lime in this shape may work as an eco-friendly low-tech material. Nevertheless, our aim is to give to our society a environmentally friendly insulation material accessible for all.

Thus, now that we know that the material works, we are working to improve its shape. In our last prototypes, we decided to re-think the brick shape and made two blocks of 36x23x7.5 cm and one of 40.5x.17.5×3 cm. The outcome looks auspicious: easier process of making, less time to dry and highly resistance after the curing process.

The next steps include coming back to the panels with a hydraulic press that may allow a faster curing process and more consistent and resistant material. We keep working in this direction to maximize the potential of this insulation.

Notes and references

1 Marques Costa, R. (2019) Crise na habitação empurra mais pessoas para casas sem condições mínimas. Publico (PT) – https://www.publico.pt/2019/05/25/sociedade/noticia/ha-viva-condicoes-precarias-sao-realidades-escondidas-1873884

2 Habitat for Humanity (year) 7 things you should know about poverty and housing. https://www.habitat.org/stories/7-things-you-should-know-about-poverty-and-housing

3 Eurostat (2019), Inability to keep home adequately warm – EU-SILC survey. https://ec.europa.eu/eurostat/web/products-datasets/-/ilc_mdes01

4 Eurostat (2012), Share of population living in a dwelling not comfortably cool during summer time. https://ec.europa.eu/eurostat/web/products-datasets/-/ilc_hcmp03

5 Eurostat (2018), Total population living in a dwelling with a leaking roof, damp walls, floors or foundation, or rot in window frames or floor – EU-SILC survey. https://ec.europa.eu/eurostat/web/products-datasets/-/ilc_mdho01

6 C.-M. Popescu, D. Jones (2017) Cellulose, pulp and paper. Jones, D. Brischke, C. (Eds.) Performance of Bio-based Building Materials. [pp.75] https://doi.org/10.1016/C2015-0-04364-7

7 China Impacts Price of Recyclable Cardboard. https://www.phswastekit.co.uk/blog/posts/10-07-2019/-china-impacts-price-of-recyclable-cardboard

8 Eurostat (2016), Generation of waste by waste category, hazardousness and NACE Rev.. https://ec.europa.eu/eurostat/web/products-datasets/-/env_wasgen

9 Eurostat (2016), Treatment of waste by waste category, hazardousness and waste management operations. https://ec.europa.eu/eurostat/web/products-datasets/-/env_wastrt

10 Nubie, S. (2019) How to make papercrete: the ultimate building material for off grid living. Homestead Survival Site. https://homesteadsurvivalsite.com/how-to-make-papercrete/

11 Andrew, R (2019), Global CO2 emissions from cement production, 1928-2018, Center for International Climate Research. https://doi.org/10.5194/essd-11-1675-2019

12 IEA (2019), Tracking Industry, IEA, Paris. https://www.iea.org/reports/tracking-industry/cement

13 Recycled cardboard provided by Lipor – local trash collector company.

14 Over time, we realised that cardboard sweats the ink printed on it, so then we tried to avoid printed parts as much as possible.

15 Natural Hydraulic Lime NHL 5 NP EN 459-1.

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DISCLAIMER

This article explains how to protect wood from pests, water and fire showing different environmental-friendly techniques

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DE BLOWA

UseProtectionLimitationInterior & exterior wood,
termites-infested woodKilling and repelling termites and other pestsIf a change in colour is not appriciated

DE BLOWA is a mixture of proven anti-termite and anti-pest ingredients that we at Critical Concrete used to protect almost all of the wood we use. So far, we haven’t done any long-term research into its effectiveness, but we’re optimistic that it’s a very useful combination because all of the ingredients are individually useful treatments for pests. The name is an abbreviation for the materials it contains:

DEDiatomaceous Earth100 gB
Borax100 gLLinseed Oil3 kgOOrange Oil100 gWAWood Ashes100 g

It is important to shake the mixture well before application, as the ingredients are not dissolving and settling on the bottom of the container. Then the mixture can be easily applied with a brush (or for a larger surface with a paint roller). Users should be aware that DE BLOWA gives the wood a darker shine. If a fine result is required, the excess should be removed a few minutes after brushing with a cloth.

ProTip: If the wood is already infested, it is recommended to briefly pull the wood through fire from all sides to kill the termites. Another option is to inject orange oil into the visible termite tunnels with a syringe. Read more about the single ingredients and techniques in the following article!

Interested in using this technology in your project?

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Introduction

Wood is a versatile and renewable material with a positive carbon footprint, which proves to be a significant construction material in sustainable architecture. Because of its strong and lightweight characteristics and the possibility to be processed and worked easily, it is a good replacement for other, less ecological materials. Additionally, wood is a relatively cheap material and gives any construction a cozy and natural atmosphere.

All these advantages make wood one of our most used materials within our projects. For example, instead of concrete or metal, the heavy load of our green roof is carried by strong wooden laminated beams of 12x48cm. Also, reclaimed wooden windows are giving a unique touch to the backyard facade of our workshop.

Beams carrying the green roof

The facade in process

Despite the mentioned advantages, wood as a building material still faces some persistent prejudices, which can lead people to refrain from using wood in their constructions. Many bacteria, fungi and insects find wood appetizing, and humidity and moisture can lead to its early decay. Besides this, a misconception associates wood with being very flammable and thus, a risky building material (when in fact wood retains its strength longer and at much higher temperatures than steel [1]). So, if wood is prepared and treated in an appropriate way, it can be turned into a long-lasting, water- and bacteria-proof as well as fire resistant building material. Many still-standing examples prove that wooden structures can last over centuries and, taking their time of origin into account, that wood can be protected without any artificial products.

House on the Faroe Islands

When it comes to protecting wood from the mentioned dangers, one can already find a lot of articles on the internet. In this article we avoid the commonly used methods which often involve ingredients harmful to the environment and instead focus on the natural and non-toxic techniques. Besides, we want to promote and facilitate the usage of reclaimed wood. The basics of how to prepare reclaimed wood for the prevention technique can be found at the end of the article.

Based on our experience and research, this article aims to give guidance regarding sustainable and environmentally-friendly techniques to protect wood against pests, humidity and fire. What techniques fit best for your projects can be traced in the decision tree below.

Protection Techniques

Exterior and interior wood are exposed to very different conditions. Whereas both need to stand fire and pest, the wood outside is prone to much more risks as it may have to withstand heavy rain, persistent humidity or high-levels of sunlight radiation. In our projects we usually use applying borax and linseed oil for interior wood and the Japanese technique of charring wood (shou sugi ban) for exterior wood. Depending on the conditions of the property and on the available resources, a combination of techniques may be suitable.

CHARRING WOOD

UseProtectionLimitationExterior and interior wood;
preferably cedar, pine, marble, hemlock or oakagainst humidity
against pests and fungi
enhancing fire-resistance
sunlight-protectionnot suitable for glued and easily cracking wood

Charring Wood is a Japanese technique which originated in the 18th century, known as Shou Sugi Ban. The surface of the wood is burned until carbonation of the surface. The finished result is called Yakisugi. We already published an article about the technique’s history and contemporary use in architecture today, check here.

Counter-intuitively, charring wood has several astonishing advantages without involving any chemicals. The idea is to burn the surface of the wood without combusting the whole piece. Besides giving the material an interesting and unique look, the process lead to a triple protection:

fire protection – this might seem counter-intuitive, but the burning of the surface starts a carbonation of the material and thus lower the thermal conductivity. The treated material will take more time to burn in case of a fire than the regular wood.
termite and mold protection – burning wood destroys the nutritional value to insects and fungi, that regular wood gives to these species. Thus it helps to prevent the propagation of pests.
water protection – the enhanced carbonation gives the charred layer a waterproof resistance, as water slips on burned wood like over an oily surface.

TRADITIONAL STYLE
(suitable for a certain amount of similar boards)

Traditionally the technique is used with Japanese cedar. Cedar is usually the easiest species to burn because of its natural chemical properties and wide grain patterns, making it a more porous wood. In the last few years, the technique has been popularized in western countries and extended to other species of wood like pine, hemlock, maple, or oak. We used pine and beech, but we experienced that these species tend to show cracks when charring. Before burning other species of wood than the ones mentioned above, it is advised to research on previous experiences or make small prototypes. It needs to be mentioned, that once the piece gets charred, it may contract slightly and change its shape as it loses humidity. If working with very precise measurements, this needs to be kept in mind!

Following, the article is highlighting different approaches to do the burning process. For both it is recommended to choose a well-ventilated place, preferably outside, but to avoid breezes. Safety measures should include a nearby fire extinguisher, a bucket of water as well as fire-resistant gloves. Wearing flammable clothes like polyester, sawdust or any flammable items within the close surrounding must be absolutely avoided.

Traditionally in Japan, shou sugi ban is performed by bonding three planks of wood to form a long triangle and starting a fire in the resulting tube. This technique is suitable to char a bigger amount of similar boards (e.g. for cladding). The easiest way to create this triangle is to place the three boards next to each other on the ground with facing the sides to be charred upside and then folding the two outside boards upwards. The triangle can be easily fixed with wire.

One possibility is to put the triangle on a non flammable floor and start the fire at the opening at one side of the triangle. In the best case, the fire spreads over within the whole tube and it will take a few minutes to char the surfaces of the wood. Once the surface is sufficiently burned, the planks are separated and thrown to the ground to stop the burning [2]. The other possibility is to start the fire while the triangle is standing up. Therefore a stable and fire-resistant base (e.g using bricks) is advisable, best next to an also fire-resistant wall. Besides, a fire-resisting spot where the hot and probably still burning triangles can be placed later, needs to be prepared. The wooden triangle can be placed in a slight angle to the wall and the fire can be started inside the lower opening of the triangle. It is also possible to put a grill on the fire-resistant base and start a fire in there, keeping the fire slightly smaller than the hole of the triangle. That way the triangles can be just put on top of the fire and the process will be started. Once the bottom part of the tube catches fire, the fire will make its way to the top. After some minutes fire shoots will be visible on the top and after waiting another minute the triangle can be removed with fire tongs. Once the wood is placed on the prepared spot, the fire can be hosed off with water [3]. 

As it is can be an unhandy task to fix and loosen the triangles, we are working on a technique to facilitate the process. We are building a burning station, where you can easily put wooden boards and start a fire underneath. When the station will be refined, we will share the methodology and tools in another short article and in a YouTube-Video!

ADAPTED STYLE WITH A HANDHELD BLOW TORCH
(suitable for every form)

If the wood does not come in similar boards or if you do not feel comfortable with the traditional method, the wood can also be charred using a handheld propane blowtorch. For many tasks we worked with this method, for example burning the windows for the facade. Precautions for this method include the mentioned safety measures and the preparation of a fire-resistant spot to place the wood during and after the process.

Starting the process, the torch needs to be lit and the gas opened to the full, so the fire appears more in a bluish colour, meaning it is more concentrated and strong. A good distance between torch and wood lays between 10-15 cm, held in a relatively straight angle. (The distance depends on the torch, but it should be around the right distance when the top of the touching blue fire separates into orange flames).

Burning process with a handheld blow torch

It is recommended to move the torch slowly over the surfaces. In the first seconds, the grains will be highlighted in a darker colour and after the whole surface will turn darker. To get the full protection characteristics, the surfaces should turn completely black and the very first layer should start to get porous. After finishing all the surfaces, the wood needs to cool down.

The burning process

Charred board

FINAL FINISHING FOR CHARRED WOOD
(applicable for traditional and hand torch technique)

After charring the wood, one can clean it softly using a standard wire brush to remove the most superficial char and create a non porous surface, using the brush in the direction of the wood grain. This task needs some precaution. If the wood is brushed too much, its pores will be opened up again and thus the water protection layer might be lost. It is enough if the excess of the burn is removed and the texture of the drains become slightly visible. After the surface can be cleaned with a cloth or water or by using an air compressor. As final coating applying linseed oil is recommended (see the advantages of linseed oil more up in the article). 

CRITICAL CONCRETE CHARRING STATION
(Shou Sugi Ban without gas)

At Critical Concrete, we wanted to build up a tool with commonly available materials which enables us on the one side to charr wood of different sizes and forms effectively, but on the other hand, keep the process at very little risk and environmentally-friendly. Check out our Video about our very own Shou Sugi Ban Charring Station!

BORAX

UseProtectionLimitationInterior woodagainst pests and fungi
against humiditynot suitable for exterior wood (only combined with another technique or with a weather-proof resistant wood spieces)

Borax Crystals

Borax is composed of naturally occurring minerals that usually comes as a white powder, consisting of soft and colorless crystals that will dissolve in water. The structure of the boron, salt and oxygen molecules inhibit the metabolic processes of many organisms and therefore borax disinfects and kills unwanted pests and insects [4].

Be aware, that even if borax is a completely natural product, it doesn’t mean it is completely safe to manipulate. For sensitive people, contact with borax may lead to skin or eye irritation [5]. Even though borax enhances the woods protection against humidity, borate protections are only suitable for indoor wood that is protected from weather.

To prepare the solution, the mineral needs to be dissolved with water. We experimented on different percentages and concluded that the mix of 10% of Borax and accordingly 90% of water seems to be the most suitable division. When doing the mix, the water should have a temperature of around 40 degrees, so the mineral dissolves faster and in a higher quantity into the water.

Before applying the borax-mix, the wood needs to be cleaned with a wet but tightly squeezed fabric (to prevent the wood from absorbing more water) to remove dust and dirt. Just before putting the borax-water mixture, it has to be stirred again, because the solution will start settling after some time. To ensure not to apply too much water to the wood and to avoid running noses, it is recommended to wipe off any excess liquid of the paintbrush. To guarantee the effect of the borax minerals, a preferably homogeneous coverage is important. The borax must be fixed with a layer of oil, stain, lacquer or wax. (Look at the next step where we explain why and how you should use linseed).

We have to admit that using Borax as a termite repellent is the best solution we found so far, but that from a sustainable point of view it is far from perfect. The biggest and commercially most important sources of Borax are found in California and Turkey; minor resources can be found in Romania, Bolivia, Chile and Tibet. For us in Portugal that means on the one hand long transportation ways and its unsustainable consequences. But on the other hand and probably much worse the exploration of the minerals from deep layers in the earth can cause immense and devastating damage to nature and landscape. For this reason we are investigating alternatives such as wood ash mixes.

ORANGE OIL

UseProtectionLimitationInterior & exterior wood,
termites-infested woodagainst dry wood termites

Besides borax, orange oil has to be proven environmentally friendly repellent. Deriving from the skin of an orange peel it saturates the wood and gives it a shiny appearance. Thus the efficiency of orange oil against termites is debated. Some sources declare that it kills dry wood termites, but it fails to fight subterranean termites [6]. We applied little amounts of orange oil several times in a row to localized termite infections with a serine and in our case orange oil proved to be very effective. Orange oil is expensive (4 liters for around 100 €) but you never need a big quantity. For small surfaces and already infested areas it is a proper substitute for borax.

In our project we also use 5% mix of orange oil with linseed oil to protect our interior wood from future infestation. But bear in mind that if the borax will remain on your wood permanently, the orange oil would probably slowly be absorbed and loose effect with time. To our understanding it works better as a treatment than as a preventive measure.

LINSEED OIL

UseProtectionLimitationInterior & exterior Woodagainst humidity
sunlight-protection

Linseed oil exhibits many advantages and thanks to its non-toxicity and its environmentally-friendly characteristics is coming back into force lately. It can be used inside and outdoors and act as a protection for water and sunlight [7].

It penetrates deep into the wood, so it does not only saturate the surface but the whole piece of wood. It is also suitable to lock the layer of borax. It lends a golden hue to the wood which will turn to amber over time. The colour is a question of taste and due to its long drying time linseed oil may not be everyone’s favorite. But in fact, it is possible to reduce drying time by using double boiled or polymerized linseed oil [8].

Comparison between a beam with and a beam without linseed oil

To apply linseed oil is very easy, a surplus of oil needs to be wiped off from the brush before applying it to the whole wooden surface and after it needs two to three days to be completely absorbed by the wood.

Linseed oil has the advantage that it penetrates relatively deeply into the wood. But it is also possible to replace all the air contained in the wood with linseed oil. The technique uses first a vacuum to cause the air in the wood to be drawn out, followed by pressuring warmed up linseed oil into the wood structure. Once the oil has hardened, the wood cells should be prevented from absorbing any moisture. For now, this technique is common among instrument makers; at Critical Concrete we did not have the chance to experiment with it so far, but we will do in a close future (stay tuned for upcoming articles).

WOOD VACUUM STABILIZATION

Usually, this technique is done by using a sealable container and a vacuum-pump. The container is filled up with linseed oil, some sources recommend a 2:1-mixture of linseed oil and turpentin. One or more wooden pieces are put into the oil, the container is sealed and and the vacuum pump is started, going to a maximum pressure of 90 kPA (for less fragile parts the optimal maximum vacuum pressure needs to be evaluated). The second phase involves compressing the air up to 75 psi and isolating the container. It is recommended to heat the oil to a temperature around 35 degrees to prevent the oil from “boiling”. The whole thing should be left like this for about a day. After, the heating can be turned down and before starting the depression the oil should cool down for a few hours. When everything has cooled down, the pieces can be taken out of the oil. It is necessary to keep the wooden pieces in a cold environment and give them a daily wipe for the following days, as the oil may continue to sweat and thus leaving ugly patches which will later on be hard to remove. After this activity has terminated, the pieces can be removed to a warmer place to speed up the drying process (which can also involve many days). It is still questioned whether this technique is suitable for bigger pieces of wood, as we could only find examples for smaller pieces (as seen in a construction context). It has to be evaluated whether the oil can penetrate completely into big pieces of wood and if yes, if it can also dry completely. Besides making the wood waterproof, the vacuum pressure treatment adds to weight, stability and resilience of the wood [9].

LIME AND WOODEN ASHES

UseProtectionLimitationContact between ground and woodagainst subterranean termitesnot applicable on wood

Both lime and wooden ashes are alkaline, and termites do not prefer alkaline environments. This mixture was already used in ancient China, where it was usually spread on the soil to kill subterranean termites, which can also be helpful to avoid wooden construction to get in contact with termites via the soil [10]. Besides, we found some suggestions to put ashes directly in holes that derive from termites. Also a study from Uganda shows that wooden ashes (sometimes mixed with pepper or cow urine) applied to the trees and soils kept the termites away [11]. For now it seems like it is not directly applicable to wooden surfaces, because the wood’s ph is usually acidic and these of ashes and lime are alkaline. Whenever acidic and alkaline components come into contact and water is present a chemical reaction will occur. It might have been possible to predict the reaction if bringing together only a few inorganic compounds, but wood consists of a multitude of organic compounds which differ even from species to species [12]. Thus, it might be an interesting field to experiment in the future.

DDITIONAL OPTIONS SUPPORTING TERMITE-FREE WOODEN CONSTRUCTIONS

Termite-eating Worms and Fungus. There is also the possibility to attack subterranean termites (which might flow over to wooden constructions) while placing a special species of microscopic worms into the soil next to the construction – Nematodes. They come as parasitic roundworms and they will quickly find and enter the host insect’s body and start eating it from the inside. Doing so, they are releasing gut and the termite will suffer from blood poisoning and quickly die. Nematodes will go on to its next victim till they cannot find any host insect anymore and then die. Similar working species of fungus exist, too [13]. If these worms may have any potential to be put directly into a wooden construction or if they will act as a pest themselves (as for example Bursaphelenchus xylophilus does to pine trees)needs further examination.

Diatomaceous Earth. Consisting of small decayed organisms, which have dried out and become razor sharp cut the sensitive, outer shell membranes of small insects. After the insect’s shell is sliced, the extremely dry particles of the diatomaceous earth actively dehydrate and thus kill the insect in a short time [14]. Diatomaceous Earth is commonly used to kill existing pests by spraying the powder to the infested areas. If and how it is applicable as a preventive protection to be applied to the wood needs to be examined.

Sunlight. Termites might die when they are exposed to sun radiation and heat. So, furniture or pieces of wood which are mobile and where indicators of termite infestation can be indicated, might be without termites after they were put for some time into direct sun [15].

Termite traps. The favorite dish of a termite is cellulose, that is why they are craving for wood and everything which is somehow made out of wood. Cardboard boxes provide an ample amount of cellulose. If the infestation of termites is apprehend, setting out a wettendend cardboard box can lure them out of their hiding. This way will probably not lead to the total extinction of the termites in one place and it needs repetition from time to time, but every termite removed is a good termite [16].

Protective measurements deriving from the construction details

The protection of wood can be enhanced the way it is – installed in the construction. On vertical boards the water can flow more easily and thus will penetrate less into the structure. Another strategy can be to work with a ventilated wood and batten structure, securing a constant ventilation on the exposed wood. This is traditionally used in barns and today adapted to many contemporary wooden construction. If possible, exposed joints, screws and nails should be avoided, reduce possible enter spots for humidity and to obviate rusty spots.

Conclusion

Due to its environmentally-friendly characteristics and its easy-to-work with features, wood is one of the most important materials in our projects. To protect this precious material and to enlarge its usable life-circle, we discovered the mentioned techniques as the most suitable for us. One the one hand, those methods enable the protection of wood with commonly used tools or with very little acquisitions. On the other hand, they not just renounce spreading toxic material into the environment, they also prove that wood can be a durable construction material, which can replace other, less sustainable materials. Nonetheless, those techniques are not exclusive when it comes to sustainable and ecological wood protection techniques, but using these methods set incentive for a more sustainable architecture.

Building the green roof structure

BONUS-TRACK

Depending on if and how the wood was used before, the wood may need to be prepared before applying the protection techniques. This possibly includes cleaning and smoothing the wood. 

Notice: Before starting to work with wood, it is important to check the humidity of the wood (max. 20% – it is possible to use hygrometer or by comparing the weight of some size and species of wood). If the wood is too wet, it is not possible to work with it, otherwise all the effort will be in vain, you’ll damage your tools, and the wood is probably highly damaged already.

CLEANING THE WOOD

When using leftover wood, it most probably shows traces of its former life, including left-over nails, screws and other applications as well as old (and probably chipped and multilayered) paint. In case this “vintage style” is wanted, it is important to weigh the aspired look against to what extent the wood needs to be protected. Removing the leftover screws, nails and other applications will facilitate the following steps. To get rid of the paint, we suggest two tools: the classical scraper or a piece of broken glass.

When using the scraper, it is crucial not to use it in a steep angle, even if this may work more efficiently. Instead using it in a shallow angle and trying to get the scraper under the paint to protect the underlying wood from scratches.

Scraping paint by hand

Measuring

A suitable piece of broken glass for this task has a curved side. For some kind of paint, thinner glass may be more efficient, but the thinner the glass is the more likely it is to break. Also it may be more handy when the piece of glass is a bit bigger (around 10-20cm), but depending on its thickness it is also more likely to break.

It may appear that it is easier to do this task without gloves, as it brings more precision in your hands. Before taking off the gloves, changing to more tight-fit gloves can probably solve this issue. 

Changing between scraper and different pieces of broken glass, in some areas one or the other may work better. Independently of the chosen tool, the scraping off of old paint can be either an easy task if the paint happens to be brittle and already chipping, or in the worst case it can take hours.

SMOOTHENING THE WOOD

After removing the nails the wood probably looks dirty, but also new wood may also have a layer of dirt, bark or mold covering its surface. It is important to clean the surface well to make the wood receptive to the following wood-protection treatment, for example to ensure a better infiltration of pest-protection and oil. An additional advantage of the removing of the first layers is the beautified appearance of the new wood surface.

The removal of the top layers and smoothing of the surface is achieved by sanding or planing. Of course there is the possibility to sand by hand, but unless it is not a very small wooden surface that you need to be protected, it may be really better work with a sanding machine. 

While using the sanding-machine, it is crucial to put the sanding patch or belt as flat as possible on the wooden surface (of course as long as this is manageable with the kind of surface you have). It may appear that it works faster and more efficiently when the sanding paper is touching the wood at an angle. But on the one hand it ruins the result as the surface will not turn out straight and bumps can be easily created. On the other hand, it also ruins the sanding pad at the edges.

Sanding

Little corners, that cannot be reached with the sanding machine – or while using the machine could come close to very weak parts – need to be sanded by hand, or a multi-tool if you have one! The worn out patches of the sanding machine probably can be used for the parts which need to be sanded by hand.  

Now the wood is ready for protection!

Sources

[1] NZ WOOD “Which building material performs better in a fire – wood or steel?”, [Online] available at http://www.nzwood.co.nz/faqs/which-building-material-performs-better-in-a-fire-wood-or-steel/ (Last accessed in January 2020)

[2] Shou Sugi Ban “Shou Sugi Ban 101”, [Online] available at http://shousugiban.com/shou-sugi-ban-101/ (Last accessed in January 2020)

[3] Instructables “Backyard Shou Sugi Ban”, [Online] available at https://www.instructables.com/id/Backyard-Shou-Sugi-Ban/ (Last accessed in January 2020)

[4] ThoughtCo “The Chemistry of How Borax Works as a Cleaner (Sodium Borate)”, [Online] available at https://www.thoughtco.com/how-does-borax-clean-607877 (Last accessed in January 2020)

[5] Healtline “Is Borax toxic?”, [Online] available at https://www.healthline.com/health/is-borax-safe#safety (Last accessed in January 2020)

[6] Networx “Does Orange Oil Work for Termites?”, [Online] available at www.networx.com › article › does-orange-oil-work-for-termites (Last accessed in January 2020)

[7] The Craftsmen’s Blog “How To: Use Boiled Linseed Oil (Safely)”, [Online] available at https://thecraftsmanblog.com/how-to-use-boiled-linseed-oil-safely/ (Last accessed in January 2020)

[8] ARDEC “Linseed oil, a natural solution for Wood Finishing”, [Online] available at https://ardec.ca/en/blog/22/linseed-oil-a-natural-solution-for-wood-finishing (Last accessed in January 2020)

[9] Good Bagpipes “Vacuum and pressure oil treatment of wood”, [Online] available at https://www.goodbagpipes.com/index.php/about-me/writings/pipe-making/131-vacuum-and-pressure-oil-treatment-of-wood (Last accessed in February 2020)

[10] Abdalla House “Termite deterrents”, [Online] available at https://www.abdallahhouse.com/2009/11/termite-deterrents.html (Last accessed in January 2020)

[11]P. Kiwuso, G. Maiteki and J. Okorio “Indigenous methods of controlling termites in agroforestry in Uganda”, 2015, Kampala, Uganda

[12] Passivhaus “LA PRESERVATION DES BOIS DANS LA CONSTRUCTION” [Online] available at https://passivhaus.fr/wp-content/uploads/2017/11/traitementsalternatifsdesboisdeconstruction-1.pdf (Last accessed in January 2020)

[13] Varsity termite and pest control “All-Natural Ways of Eliminating Termites” [Online] available at https://varsitytermiteandpestcontrol.com/natural-ways-eliminating-termites/

[14] Citypests “Diatomaceous Earth for Termites”, [Online] available at https://citypests.com/diatomaceous-earth-for-termites/

[15] Pesthow “How to get rid of termites”, [Online] available at https://www.pesthow.com/how-to-get-rid-of-termites/

[16] Pesthow “How to get rid of termites”, [Online] available at https://www.pesthow.com/how-to-get-rid-of-termites/

[image by Vincent van Zeijst], [Online] available at https://commons.wikimedia.org/wiki/File:Faroe_Islands,Streymoy,_Kirkjub%C3%B8ur(1).jpg (Last accessed in January 2020)

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