Category: Concrete

Researching new methods of wood protection are of key importance for the work we do here at Critical Concrete. Wood is the primary material we use to build and renovate houses; from the structure, to the cladding, and the furniture. Priorities of our wood protection solutions include; relatively low-cost, accessible materials, simple recipes. Prioritising these aspects means it is easy to scale up for large projects.

Tricoil

For our renovation project in Esposende, we rebuilt the roof with a wooden structure, so it was essential to protect the wood for the longevity of the building. With the cladding substructure, window lintel, and furniture we had a lot of wood to treat. Through research of various recipes we came up with a recipe and method which fit the requirements we had.

TRICOIL (Turpentine/Tung Raw Linseed I Coconut OIL or 3 oil) is a blend of three different oils which gives protection from parasites and environmental conditions. Linseed oil, Tung oil, and Coconut oil are blended together using turpentine as a solvent to combine the oils and allow for deeper penetration of tricoil into the wood. The original recipe and method we based this upon can be found here [1].

Tung oil has been used by the Chinese for hundreds of years to protect wooden boats. It is derived from pressing the nuts of the Tung tree. It has anti-termitic properties and offers durable waterproofing.

Raw Linseed oil, obtained from pressing flax seeds, creates a water repellent barrier on the wood.

Coconut oil, rich in fatty acids, nourishes and protects the wood.

Turpentine, a solvent derived from tree resin, thins and blends the oils for easy application to the wood.

Method

Ratio of ingredients for TRICOIL

Heat a large pot of water to 50°C to act as a bain-marie. Place a jar of coconut oil and turpentine into the bain-marie and cook until this mixture has also reached 50°C, stir often. If you have a big enough pot, you can do the same with the linseed oil and tung oil together in one jar, placed in the bain-marie. Once the mixtures have reached the temperature, mix them together.
The Tricoil is now ready to be applied on clean, sanded wood. Apply to the wood once per day for 3-4 days and dry in an open space.

Burning Station

Since discovering the wonders of Yakisugi, it has become a firm favourite as a method of protecting wood in many of our projects. Our first article in wood protection dives into the science of the method and the properties of charred wood.

After a fair few projects using our brick burning station at CC HQ, we enlisted it for charring wood for the cladding of the Esposende house. Around a half ton of bricks were put in the van and rebuilt on the street. After so many uses at such high temperatures the normal bricks and even special fire-bricks began to crack and posed a risk of collapse while using the stove. Thus we decided to design a new, super-portable, efficient charring station.

Blueprint of the new charring station

The body of the charring station consists of an old oil drum, an inlet for passing the wood to be treated through, a feeder for fuel, and a hole to attach a chimney. It mimics the previous charring station with the L shape encouraging an upward draft. The feeder is made of an old fire extinguisher welded on with extra metal for support.

With the use of two rollers, 1 person can manage the charring station themselves. If the fire is burning well and frequently stocked, it is possible to char a 3m 30x3cm board in 10-15 minutes for both sides.

The efficiency and speed of this burning station allowed us to burn all the wood for the board and batten cladding of the house in Esposende. Furthermore, this higher degree of flame control allowed us to achieve a uniform result for the boards to not warp and lose their integrity.

For improvements of the burning station we would advise a metal plate on the lip of the openings for the board to rest on – otherwise it can mark the board. Additionally, a way to adjust the opening for different sizes of boards would increase the efficiency by reducing excess draft.

Top Tips

Have an ample supply of fuel available to keep the fire well stocked and at a medium-high flame.If the flame is burning too high it is better to do a few quick passes to avoid over-charring the wood which can result in warping.Apply raw linseed oil after charring to compensate for loss of moisture and flexibility.If the wood does warp and you are using it for board and batten cladding, mount the board with the bend curving away from the wall to reduce pressure and prevent cracking.

There are a few drawbacks of this method and these should be considered before employing this technique in your own projects. One is the time intensive nature of the process. The burning station was fired up most days of the 6 weeks of Esposende workshop. This works if there are many hands available to take on the relatively low-skill task and take turns amongst each other. However it may prove tiresome for a self-build project. The second drawback is the issue of smoke. At Critical Concrete HQ we have neighbours in close proximity, requiring us to build an extra tall chimney to prevent smoking out the neighbours. Having ample space is also a factor to consider. The actual working site of Esposende was relatively small, however, we were lucky to be able to use the quiet street, much to the amusement of the neighbours! Looking to our next renovation project we will need to contain construction activities as much as possible as the street is very narrow with no pavement. For situations when these drawbacks are apparent we endeavour to find more suitable solutions.

New burning station

Yakisugi cladding on wooden substructure treated with TRICOIL

Swedish Paint / Flour Paint

Filling the requirements of cheap, scalable, non-toxic and accessible ingredients, Swedish Paint is an excellent choice. Swedish paint has long been used as the primary choice for wood protection in many Nordic countries. It can endure the harsh climate while offering an appealing aesthetic.

Swedish Paint can last for up to a decade before a new application is needed.
Photo by Anders Nord

Method

This is a new method for us and we have tried out one recipe using the materials we had available in the workshop [2].

For 3 litres of paint the following measurements can be used:

300g of flour3l of water600g of pigment300ml of linseed oil

For pigment, we used red clay that we had left over from making a rammed earth floor and wood ash from a local saw mill. There are many options for pigment, do some research and see what is available in your local area.

This is the very beginning of our research with Swedish paint so there will be more information to come in the future as we experiment with different recipes and ingredients. We will leave these samples outside to see how they withstand the weather.

Paint samples using wood ash and clay

References

[1] ​​https://www.artamin.it/impregnante-ad-olio-fatto-in-casa/

[2] https://engelleben-free-fr.translate.goog/index.php/recette-de-la-peinture-a-la-farine-protection-des-bois-exterieurs?_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=ajax,elem&_x_tr_sch=http

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Cooperative housing is discussed in one module of our Sustainable-Sustainable Architecture postgraduate course; if the topics discussed in this article pique your interest, you may be a wonderful candidate. Learn more here.

Introduction

Living in a single-family unit, either in a house or apartment building has become the living standard, but it isn’t the only possibility. Many houses are equipped with appliances and rooms that are used rarely or on a weekly basis, which suggests that there may be a more functional system out there. On the other hand, many houses in urban settings are cramped and unhealthy due to the rising cost of living in cities and urban migration. This inequity is only growing with urban migration patterns and gentrification.

The single-family housing model is not a viable paradigm for the future. Not only is it an inefficient use of space, but it is also isolating and fails to nurture community. It tends to be cramped for the poor and leaves vulnerable groups to fend for themselves. On a deeper level, these aspects are the exact opposite of what allowed early humans to create society.

Architects, theorists, and dreamers have all wondered how our dwellings can be reshaped for better quality of life and higher affordability, but to solve these issues, they don’t need to strive for the most complicated answer. Two possibilities already exist to challenge the housing paradigm. Housing cooperatives have existed for over a century and challenge the notion of housing as a commodity. Cohousing is a method of living with others to maximize space, resources, and community. These ideas have potential to not only remedy urban housing challenges, but also to home in on environmental sustainability in domestic spaces.

a basic comparison

Cooperative Housing

Housing cooperatives, or co-ops, have existed throughout history, yet in most places they are not recognized as mainstream housing possibilities. In fact, they’ve gone so far under the radar that you might be wondering what in the world a housing cooperative is. Let’s rewind.

A housing cooperative is a housing business which has shared ownership by its residents.[1] The goal of this collective ownership is affordability rather than profit.[2] Aside from collective ownership, there is one feature that is almost always present in coops: democratic processes.[3] Residents get to vote on the major decisions of the cooperative, such as who can replace a former resident, or whether solar panels should be purchased for the building. Other important elements of cooperative housing are commitment to social goals, security in community, decent housing, personal growth, and transparency in management.[4]

The modern history of housing cooperatives in Europe began in the 1800s in Berlin with Victor Aimé Huber’s cooperative dwellings.[5] The practice evolved and expanded, becoming an opportunity for decent affordable housing and as a possibility for people to have more control over their living conditions.

Kalkbreite Cooperative in Zurich

Differences between Cooperatives

As the practice of founding co-ops spread and grew more prevalent, many differences arose. There are limited-equity coops, often for low and moderate income shareholders, market-value ownership coops, which do not require affordability; rental co-ops which have more secure tenure and have mixed-income tenants; and mutual aid co-ops which are based on solidarity and self help and are usually self-built.[6] Depending on the country and its policies, funding a new housing cooperative could rely on government, banks, or private investors. Cooperatives can be rural or urban, high rise or groups of single family housing.[7] Some co-ops began as ventures to create exclusive and wealthy multi-family housing whereas others were intended to create housing for the poor.

The most pronounced differences between cooperatives comes down to financing and legal constraints, both of which are influenced by the government where a cooperative is located. Cooperatives around the world vary subtly because of governmental constraints in their respective countries, so these are a few examples to show the possibilities.

In Austria, a country with a strong social housing sector, housing cooperatives which are below market-rate are exempt from corporation tax.[8] The government offers subsidies through public housing schemes via low-interest grants or mortgages that cover some of the construction costs.[9] In Egypt, cooperatives are exempt from many taxes, from industry profit taxes to custom taxes and importing fees, some fees including building license fees and publishing fees, and interest of deposits in banks.[10] They receive a 25% discount on state owned land which can be increased to 50%.[11]

FCH Housing Project in Egypt

Portugal’s government reduces the VAT from 20% to 5% for cooperatives, and they also provide tax exemptions on land acquisitions and subsidize interest rates for cooperatives with low-income target groups.[12] Pakistan has a unique system for cooperative development: the state provides land to cooperatives, but cooperative shareholders are responsible for the construction of their residence on the plot they are assigned.[13] Interestingly enough, in Germany, although housing cooperatives do receive tax relief, they do not receive money from social housing funds; co-ops are not part of social housing there.[14]

The presence of housing cooperatives often hinges on politics. Since cooperatives greatly benefit from the aforementioned subsidies, tax relief, government loans, and other governmental support, proliferation of new co-ops can fluctuate with political changes. Furthermore, governments can incentivise cooperatives through policy, but they can also place limits on the founding of new cooperatives. For instance, Poland banned cooperatives in 1990, a marked difference from the years they had spent becoming mainstream during the socialist regime.[15] On the contrary, Portugal experienced an increase in co-ops after an authoritarian government which opposed the values of cooperatives was replaced.[16] In Pakistan, a corruption scandal from a cooperative paused registration of new housing cooperatives.[17]

Membership practices in cooperatives mean that even in rental cooperatives, residents are less passive inhabitants than in typical multi-family housing. Democratic foundations within cooperatives mean residents vote on management, changes, and governing structures. Each shareholder can have one vote, but in some co-ops the number of votes is equal to the number of shares. Some cooperatives require all decisions to be voted on by everyone, whereas others allow members the option of voting. Whichever way the voting system plays out, members of cooperatives have a stronger sense of ownership and participation, and can motivate one another to create a greener, healthier housing cooperative.

Student Cooperative in California via tsakett on Flickr

Cohousing

Cooperative housing shouldn’t be confused with cohousing, a modern iteration of intentional living developed in Denmark.[18] Cohousing can be implemented within cooperative housing; the two are separate systems which have potential to work together. Cohousing challenges the single family home in favor of sharing space and creating a stronger community.

Although the idea of living with others isn’t new, the term “cohousing” only arose in 1988 after two architects from the United States observed the phenomenon in Denmark, where it had gained traction.[19] Exactly twenty years prior, architect Jan Gudmand-Hoyer had spent several months discussing housing alternatives with a group of friends, developing plans for 12 houses gathered around a common space.[20] Although the project never took form, he published an influential article on the project entitled “The Missing Link between Utopia and the Dated One-Family House” which elicited responses from many families eager to live in such a situation.[21] Another article, “Children Should Have One Hundred Parents” by Bodil Graae, garnered further interest in the concept.[22] After the articles were published, families came together to purchase sites and construct two projects by 1973, which formed the blueprint for cohousing in Denmark.[23]

Rudolph Schindler House in Los Angeles via Lian Chang on Flickr

The ideas are far from new. While Gudmand-Hoyer and Graae were writing these articles, the hippie movement in the sixties was awash with communes and ideas challenging single-family living. But unlike cohousing, many hippie communes were infamous for being financially and socially unsustainable. Additionally, with roots in the early 1900’s, the intentional communities called kibbutz are well known examples shared living from Israel. In California, the Austrian architect Rudolph Schindler built one of the first ever modernist houses, designed for two families to live cooperatively and share one common kitchen.[24] All this is to say that cohousing is not a particularly unique idea, although its less radical stance is possibly what makes it such a viable housing option.

However, what differentiates cohousing from similar ideas like kibbutzim or ecovillages is that cohousing is primarily an architectural design which fosters community alongside a social agreement to live cooperatively. It does not have ideological connotations and can manifest in various ways. Cohousing can be rural or urban, meaning unlike other kinds of intentional communities, it can respond to the global urban influx. Additionally, cohousing may be equipped to handle the challenges of  urban living, such as elder- and childcare along with social isolation. Some cohousing situations share chores in common spaces such as cooking, which tends to free up time for those with busy schedules.

Spreefeld Berlin Via MitOst on Flickr

Sustainability in Cohousing

Cohousing has some inherent advantages for sustainability. First, dense dwellings groups are more efficient to heat or cool. If the kitchen and living areas are shared, less furniture is needed and kitchen appliances only need to be purchased once for multiple families. By living in close proximity, people can share their skills, which means residents can help each other with tasks like repairing broken items instead of wasting them and buying new things. Additional benefits include purchasing food in bulk, which is better for transportation and uses less packaging. Shared garden spaces mean some food can also be cultivated in a community garden. Having a garden also provides a space to incorporate a compost bin, a challenging feature for typical urban housing.

Cohousing also has the benefit of community learning and social practices, which helps propagate care for the environment and ecological values.[25] By living with many people, there can be less car dependence. Tasks like grocery shopping can be divided and commuting to work can be done with fewer cars.[26] Finally, shared meals can result in lower food waste.[27]

Vauban Cohousing in Freiburg

Housing More Sustainably

There is potential for even more sustainability in cohousing projects. The fact that many cohousing projects are cooperatively owned, purchased before construction is complete, or even designed with input from the future residents is something that allows for even more ecological interventions. If cohousing projects are designed with sustainability in mind, they can be more energy efficient and prioritize passive sustainable strategies. For instance, common areas can incorporate daylighting and efficient ventilation. The design can include a root cellar to store vegetables for long periods in winter without the use of a fridge. Natural materials such as hempcrete, mycelium, cork, rammed earth and many more could all be used as building materials. Since some cohousing projects include aspects of self-building or auto-construction, materials and techniques are employed with easy repairability and designs that factor in longevity. Some features of sustainable design, like solar panels, come at a premium, but if a project is cooperatively owned, these additional costs are spread out among all the owners.

Occupant ownership via the housing cooperative model also means that there can be experimental sustainable practices that wouldn’t usually be possible in conventional multi-family housing. A garden could be designed to have a phytodepuration wastewater treatment system, which would simultaneously provide a beautiful marsh landscape in the common area. There could be compost toilets, green roofs, or food forests, too. With an ecological group of residents, there is also potential for the use and maintenance of a biodigester to produce biogas for cooking. The possibilities are endless, especially with lots of community minded people with various skills willing to contribute to communal projects.

Conclusion

Cohousing and cooperatives are two approaches to financial and ecological housing issues. They provide a peek into what housing would look like if we didn’t approach it from a single-family perspective. When the concepts are combined, they create feasible models for better living conditions, affordable housing, and stronger communities. Moving away from profit and towards collective action gives an added opportunity for a more ecological way of living. Existing cohousing cooperatives are great launch pads for pushing the possibilities of environmentally sustainable multi-family housing, while budding cohousing cooperatives have the opportunity to design healthy living spaces for both people and the planet.

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Let us introduce the newest addition to our production center in Porto: the compost toilet! Although human waste is a taboo subject, we will be talking about poop a lot in this article. After all, if you refuse to address a topic, how can you challenge the conventional and unsustainable systems that surround it?

One unsustainable aspect of conventional toilets is water. Most toilets in wealthy countries use potable water to flush toilets, but water is a resource that is becoming scarce amid rising global temperatures. [1] [2] Even if this were not the case, the fact we contaminate drinking water on purpose reflects a dire need to challenge this convention. Human excrement, ironically, is a valuable resource. It can be used as a source of food for bacteria. Sewage, as well as diseases linked with fecal contamination of the environment, can be eliminated when composting is adopted as a sanitation method.[9]

In our phytodepuration article, we explored one alternative method for wastewater treatment. It consists of a marsh-like condition, in which greywater and blackwater are filtered and purified using plants. Compost toilets are the inverse; they require no water and use dead plants rather than living ones. Essentially, microbes break the waste down into humus, a completely decomposed organic material. Besides feces, the other necessary ingredients for composting are straw, sawdust, dead leaves, or wood chips. These carbon-rich materials are known in the composting world as “browns,” while the nitrogen-rich feces make up “The Greens.” The balance of browns and greens is crucial to successful decomposition; a composting toilet without carbon-rich material would not result in compost and would be a health hazard. Additionally, the browns act as a cover material to expunge smells.

Across the world, different prototypes of compost toilets are being tested within diverse capacities and contexts. One such example is the project Mobile Dry Diversion Toilet in Lagos developed by FABULOUS URBAN with several partners since 2017. The project targets families in low-income communities who do not have access to domestic sanitation. This prototype separates the urine and feces into different compartments, which finally facilitates the process of composting. [4] The urea present in urine degrades into ammonia while not only has an off putting smell but also is the reason for the extermination of the bacteria that would otherwise break down the waste.[5] For further explanation, you may follow the link to the original article. Mobile Dry Diversion Toilet

Mock-up prototype being constructed to be tested for the project Mobile Dry Diversion Toilet Photo. © FABULOUS URBAN

Public acceptance, regulations, and a lack of expertise and experience in composting toilet design and operation are all obstacles to the use of composting toilets in urban environments [3].

We have been testing our system here at the Critical Concrete office.

COMPONENTS OF OUR SYSTEM INCLUDE:

a large compost pilea toilet chambera bucket within the chambera seat for the chamber

The assembly of components of the our compost toiletTo use the compost toilet, users cover their poop with a layer of carbon-rich material. In our case, this is mostly sawdust because it is a waste material that we always have on hand. Once the collection bucket in the toilet is full, we empty it into the outdoor compost pile dedicated solely to the compost toilet. The fresh layer of waste is covered with more sawdust, which immediately removes the smell and wards away flies. We then rinse the bucket, pour the rinsing water on the compost pile to help moisten the compost pile, and cover the compost pile again with fresh sawdust.

Our compost pile setup

We use our compost primarily for feces as we are an office which means the usage of this toilet for urine will be more than feces. The imbalance of the proportion of urine and feces could result in a slower composting process. A low level of urine is not an issue for the decomposition, but with our compost pile located near our living space, we want to avoid the smell that it can cause. In the active compost pile, the waste completes its conversion into humus. The temperature at the core of the active compost pile can reach upto approximately 650C. The covering material such as saw dust, hay, weeds, straw is referred as biological sponge in the figure on the right. Once the compost pile is high enough, we leave it to cure for oneyear, after which it is safe to use for gardening. The curing time for compost containing human waste is longer than most compost piles, but it ensures the extermination of pathogens present in the feces before its use.

Section through the compost pile © The Humanure Handbook: shit in a nutshell

Temperature reading from our active compost pile

Making a functional compost toilet can be challenging, so of course, we had to manage some difficulties.  First, the volume of our waste output is disproportionate to our available yard space. After just three months of using the toilet, the compost pile is half-full. Since the active compost pile still needs to be cured once it is ample, we may have to pause our use of the compost toilet at that point. If we had unlimited space in our yard, we would have had the chance to start a new compost pile. But in an urban setting like ours, that is not an option. Our second challenge is that our active compost pile is dry because we use a lot of sawdust. In order to create a hospitable environment for the suitable bacteria to break down our waste, we need to add moisture to the pile. At this point having some levels of urine present in the compost pile would help but, we use some greywater from washing dishes instead in order to avoid washing drinking water and unpleasant smell of urine. It will be also good to mention that according to “the Humanure Handbook: shit in a nutshell” by Joseph Jenkins for a household the separating urine and feces is not necessary.[9]

Rich fertile compost

Even though there are some obstacles to using a compost toilet, especially in an urban environment, the system is quite simple overall. For us, it is a way to transition from relying on a flush toilet and better our water usage while producing garden material. We will update our progress on this blog and our social media as we adapt to this new and improved option for human waste management in our headquarters.

Do’s and Don’ts © The Humanure Handbook: shit in a nutshell

Bibliography

[1] United Nations, “Scarcity | UN-Water,” UN-Water, 2011. https://www.unwater.org/water-facts/scarcity/.

[2] E. Saner, “The no-flush movement: the unexpected rise of the composting toilet,” The Guardian, Dec. 09, 2019.

[3] C. K. Anand and D. S. Apul, “Composting toilets as a sustainable alternative to urban sanitation – A review,” Waste Management, vol. 34, no. 2, pp. 329–343, Feb. 2014, doi: 10.1016/j.wasman.2013.10.006.

[4] “Mobile Dry Diversion Toilet FABULOUS URBAN,” Swiss-Architects. https://www.swiss-architects.com/en/fabulous-urban-zurich/project/mobile-dry-diversion-toilet?nonav=1 (accessed Oct. 06, 2021).

[5] N. Rogers, “Composting toilets could be the way of the future,” ABC News, Jun. 24, 2019.

[6] T. Avellán, “The world needs more toilets – but not ones that flush,” The Conversation, Mar. 21, 2017. https://theconversation.com/the-world-needs-more-toilets-but-not-ones-that-flush-74007 (accessed Oct. 07, 2021).

[7] “Saving water in the home,” nidirect, Oct. 20, 2015. https://www.nidirect.gov.uk/articles/saving-water-home.

[8] N. Hancock, “Safe Drinking Water Foundation,” Safe Drinking Water Foundation, Nov. 30, 2016. https://www.safewater.org/fact-sheets-1/2017/1/23/water-consumption.

[9] J. C. Jenkins, HUMANURE HANDBOOK : shit in a nutshell. S.L.: Chelsea Green, 2019.

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