First course of 2016

Poster 04_2016 sml

TERRA Award ~ first international prize for contemporary earthen architecture

Earth is becoming increasingly popular in contemporary architecture: hundreds of projects of high aesthetic and technical quality are emerging across five continents. This material, which has low embodied energy, is readily available and appropriate for participatory buildings. It could help provide a solution to the needs for ecological and economical housing.

To enable both professionals and the general public to fully appreciate this building material, the following partners have taken the initiative, under the auspices of the UNESCO Chair “Earthen architecture, construction cultures and sustainable development”, to launch the first international prize for contemporary earthen architecture: the Labex AE & CC-CRAterre-ENSAG Lab research unit, the amàco project, the Grands Ateliers, the CRAterre association and EcologiK/EK magazine.

Wang Shu, 2012 Pritzker architecture prize laureate, is the president of honour of this TERRA Award, the trophies for which will be presented in Lyon on July 14, 2016 at the Terra 2016 World Congress.

Context

Since its creation in 1979, the CRAterre-ENSAG Lab has been considered as the international research and training reference centre for earthen construction. It will organize in July 2016, under the auspices of the UNESCO Chair “Earthen architecture”, the Terra 2016. This World Congress takes place every four years on a different continent and will be held for the second time in Europe. It is expected to draw around 800 professionals, teachers and researches to Lyon (France).

The TERRA Award was initiated within this framework. It will be the first international prize for contemporary earthen architecture and a natural furtherance of the national award launched in 2013 in France by CRAterre-ENSAG, AsTerre and EcologiK/EK magazine.

Objective

The purpose of the TERRA Award is not only to identify and distinguish outstanding projects, but also to highlight the audacity of the project owners for choosing to use earth, the creativity of the designers and the skills of the craftsmen and entrepreneurs.
An itinerant exhibition will feature 40 buildings from all continents, constructed using various techniques (adobe, cob, CEB, rammed earth, plaster, etc.) for all types of programs: housing, public facilities, activities, and exterior and interior designs. The exhibition will be completed with lectures and workshops by CRAterre-ENSAG and the amàco project.
The search for outstanding achievements deserving of this prize and the associated exhibition will make it possible to generate the first worldwide database on contemporary earthen architecture. The resulting virtual library will be available both to the general public and professionals via this website.

Involved projects

The projects must have been completed after January 2000.
There are eight categories covering all types of programs, whether new or renovated:

  • Individual housing
  • Collective housing
  • School, sports and health facilities
  • Cultural facilities and religious buildings
  • Offices, shops and factories
  • Interior layout and design
  • Exterior design, art and landscape
  • Architecture and local development

Text from the Terra Award website.

Owner-builder journey ~ Franz Muhl: Energy flows where attention goes

In this edition of the Owner-builder journey, Franz Muhl writes about a mud brick addition to his Scarborough home.

Franz 1

Five years ago, Peter McIntosh gave me +- 900 sun-baked mud bricks, for an extension to my house. Franz 3With little start up money, a trickle of income, some plans on google sketch up, a pickaxe and, most importantly, plenty of time, I finally started the process a year ago.

 

At foundation level, with the skills that I had at the time, I used clay-fired bricks and a bitumen coat for damp-proofing. Franz 4In March, I headed off to Berg-en-dal for a crash course with Peter. He traded his skills and knowledge in natural building for mine in brewing beer. To take clay, sand, water and a bit of straw in the right proportions and work it into a material for building, was a big revelation for me. Continue reading

CPD accredited natural building course: Materials and techniques

We’re excited to announce the first course of the year will be taking place from 26 April – 2 May, at Wild Spirit Backpacker’s lodge in the beautiful Nature’s Valley. Email naturalbuildingcollective@gmail.com to book your spot!

CPD accredited Natural Building 7 day course_April_WS

 

 

Understanding earth III: Plaster and mortars mixes

(Please note that in order to understand what is written here you will need to have read my previous posts on understanding earth and testing earth)

Plasters and mortars are by far the process that I get asked about the most, and for good reason as plasters are what protect the building from the elements and give them their beautiful finish. Understanding how the material is going to behave right the way through the process, plasters and mortars should be planned for from the beginning. Plasters that are not planned are plasters that fail and if they do the building not only looks unsightly but loses a valuable layer of protection.

As discussed in the earlier articles on understanding earth and earth testing, it is important to establish the most appropriate earth mix at the beginning of the building process. This mix quite literally informs the whole building process from the ground up to the last 3mm of plastering. The initial testing phase establishes a basic cob mix that has both sufficient compressive and tensile strength and has acceptably low cracking. It is important to have an idea of how you will approach each phase and ensure that the different materials ‘talk to one another’ to prevent excessive cracking and delamination, which are the most common failures associated with natural building. Essentially the same original mix is manipulated to be appropriate for different areas, depending on the purpose. Areas that will require the original mix to be manipulated are, amongst others, the foundations and plasters.

It is important to remember that there are as many mixes as there are building sites and what follows is just a taste of what is possible. Over the years one comes to settle on a strategy that works and begins to perfect it to prevent failure. What follows works, but is by no means the only way and is one amongst many.

Let us imagine that the mix you worked out after the testing phase was two parts clay and three parts sand, i.e. 40% clay earth and 60% rough sand, and straw. Just an aside, this formula would indicate that there is a percentage of silt present in the clay earth (often the case), otherwise the clay percentage would usually be lower.

Let’s start with a mortar mix for the foundations. Firstly you will leave straw out of the mortar mix for the foundation, as it would degrade with any moisture. Obviously the foundation should be able to resist water, so using un-stabilized mud-bricks or cob is not possible; ideally you have rock available.

Lime is often seen as the answer to stabilise mortar mixes, as it hardens over time especially when exposed to moisture. However, lime is not friendly to the environment due to the high embodied energy i.e. the energy used to create the product. Over time lime does re-absorb the gasses given off by it during its production, the energy required in this phase is considerable and may well come from a polluting source such as coal. Furthermore, lime is quarried or produced by crushing coral. Lime also makes the material more brittle and prone to cracking, even though the material gets a lot harder, compressive strength is not everything. Often, lime is considered to be better than cement, not because it is less damaging to the environment, but rather because it is naturally occurring and an ingredient of cement. So the strategy should be to minimize its use.

Earth mixes are more plastic and able to resist a certain amount of movement so care needs to be taken just where you apply the lime. However the use of lime is beneficial in foundations where the pros of lime, its hardness and resistance to moisture, are required. With the earths in our example, a mortar mix that will work with the rock foundation is 30% clay, 50% sand and 20% lime. This keeps the material as close as possible to the original mix while getting the benefits of the lime right where you need it. If you pay attention to how the rock work is done you will minimize the use of the mortar and thus minimize the use of lime.

As your house is exposed to variances in temperature and humidity, you want to prevent the materials in the walls from moving at different rates as it causes delamination and cracking, which is in my opinion, the number one reason for a natural building failing. To help prevent this you need a good mortar mix. This is an area that your mix does not need to be manipulated. Between your mud bricks it is ideal if you stick to the original mix that came directly out of the testing phase, including straw.

While some imperfections are fine in the foundations and mortar mixes, any imperfection in your plaster mix will have dire consequences for you final finish. This is mainly because there is generally no amount of acceptable cracking in the final plaster as this leaves the building vulnerable to water erosion. In a nutshell, plaster provides the final finish look and provides protection from the elements.

I have adopted a three phase approach to plastering that is well accepted and works. The first is the scratch coat, the second the form coat and lastly the final plaster coat. The scratch coat is your original cob mix applied to the mud bricks to give purchase to the subsequent layers. It includes straw and is left rough often with lots of fingertip marks.

Scratch coat on this straw bale building near Groot Marico includes more straw and is left rough and textured.

Scratch coat on this straw bale building near Groot Marico includes more straw and is left rough and textured.

The form coat is just what it says and creates the final shape of the building. At this stage it is best to leave out the straw as you don’t want anything protruding through your final plaster coat. The form coat is hand smoothed in such a way that the final plaster coat can go on evenly with a plastering trowel or steel float. Fine cracking is still acceptable in this phase.

On this mud brick building in Scarborough near Cape Point, you can see the scratch coat on the left, while on the right the form coat cob mix, excluding straw, is being hand smoothed.

On this mud brick building in Scarborough near Cape Point, you can see the scratch coat on the left, while on the right the form coat cob mix, excluding straw, is being hand smoothed.

Prior to the final plaster you will need to do a number of tests on top of your form coat. This is done to ensure that there are no fine cracks that will lead to erosion by water. Often cracks create wonderful patterns and you may want to leave the mix to show off its beauty but only on the inside plaster. On the outside no cracking is acceptable after the material has been polished. Usually I do about four tests to select the best mix. Based on our theoretical mix for this article the four tests may look something like this.

  1. First your original mix, 40% clay, 60% sand with 5 % lime =105%
  2. Second reduce the clay a little to reduce potential cracking 35 % clay earth, 65 % sand plus 5% lime.
  3. Reduce the clay some more just in case there is still cracking to 30 % clay earth, 70 % sand plus 5 % lime.
  4. Lastly increase the clay content over the original mix, 45% clay earth, 55% sand plus 5% lime.

    The walls were still going up when we started the Final plaster test patches for this compressed earth brick (CEB) building in Scarborough, Cape Point, SA.

    The walls were still going up when we started the Final plaster test patches for this compressed earth brick (CEB) building in Scarborough, Cape Point, SA.

As these samples are applied so thin they will dry fast so decisions can be made fairly quickly, perhaps after three days or so. You will need to choose the mix that does not crack. If it so happens that none of them do, pick the one closest to your original mix to ensure that the dreaded delamination is ruled out. If you are confident that this will not happen then choosing the mix with the highest clay content will lead to a very fine finish.

Technique is as important as information when it comes to natural building and nowhere is that more important than with the final plaster mix. The final plaster mix needs to go on evenly between 3 and 5 mm thick. The mix changes slightly to include 5 % lime, but only in these last few millimetres. The reason lime is added to this final 3mm – 5mm of the walls is to improve the resistance of the final plaster to water; the percentage is kept low so that the material does not become brittle and prone to cracking, and allows the natural plasticity of earth mixes to overcome small amounts of movement and not delaminate from the wall. There is also a reaction that takes place between the lime and clay that is complete between 5 and 7 %, which greatly increases its durability.

The final plaster mix will need to be finely sieved so that bigger particles do not protrude through the plaster and the result is smooth and even. I prefer the common kitchen flour sieve. Don’t be put off, by how long you think it would take, because you really need so little for the final plaster mix that it goes quite quickly and you can do it directly into a bucket.

Here the final plaster coat is being applied to the exterior of the straw bale building near Groot Marico. It’s between 3mm and 5mm with 5% lime and polished.

Here the final plaster coat is being applied to the exterior of the straw bale building near Groot Marico. It’s between 3mm and 5mm with 5% lime and polished.

Once the final plaster is applied it is polished to provide a very smooth almost fine leathery appearance, further driving the material into the wall and providing durable weather protection. A plastic tool cut from feta or ice-cream tubs work well for this final polishing stage.

Once the plastering is complete, coat the building with three coats of raw linseed oil. Mix the first two 50/50 with mineral turpentine to ensure that the linseed oil penetrates well into the plaster. Allow each layer to dry before you apply the next. Finally a coat of undiluted raw linseed oil will finish it off.

Looking at the whole process as being one thing instead of being separate little bits helps to avoid common problems. Always pay attention to the testing phase, understanding that the same mixes you use for your bricks and mortars will be reflected in your foundations and plasters.

See our Disclaimer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

New directions in informal settlement upgrading and community-led sustainable building practices – The Freedom Square shack replacement project – Day 18 (Thursday 2 Oct’14)

I came to learn how to build a cob wall; instead I learned the story of my life before I even stepped onto the building site.

It was day 18 at the Freedom Square shack replacement building site in Bloemfontein, but my first day on the premises. The walls of Lientjie’s new house were already about three quarters completed. The first one and a half meters from the floor up was made of compounded tyres and solid cob packed firmly into and onto a reinforced metal grid. From this solid section of wall up toward the beams, the building team has started to experiment with decorative wall building techniques such as inserting colored glass bottles in patterns into the cob and carving edgings onto the walls. The total effect is of a mud wall inserted with an array of miniature skylights. It was still early morning and the sun spilled through the little skylights in mesmerizing colour.

So how does one build a cob wall? In an ideal world it would be with a rigorously tested cob mix of course. However, in this part of Freedom Square location life is hardly ideal. Here lives the abject economic disadvantaged and marginalized, those whose only option is to make do with what they have. Even the earth lacks succor and consists of 70% clay. The Qala Phelang Tala building team, as change agent and mentor, has therefore devised a method of ensuring an optimal cob mix, by mixing in a ratio of dry horse dung and fine sand.

By now each member of the regular building team has established their niche. While Ellen Maphalane and Tiisettso Chobokoane were making bottle bricks, Abraham Nkotywa was layering the wall with cob mix and finished bottle bricks. Mokoena Maphalane carried buckets of clay, horse dung, sand and water to the mixing area and all stomped the cob mix together. Tiisetso two year old niece, Pimelo, was following suit and industriously heaving water back and forth in her small porridge bowl. Anita was decorating the cob walls with her carvings while Oretile, the little boy from across the street, was avidly watching her every move. He was totally engrossed by Anita’s unique skill and the beautiful wall art that she was creating.

1.Tiisetso showing the Occupational Therapy students the finer art of refining details on the wall.

Tiisetso showing the Occupational Therapy students the finer art of refining details on the wall.

Each member of this seemingly ragamuffin building team has his/her own story of hardship and grief, adversity and woe. Abraham is 62 and has suffered from cancer, interspersed with periods of remission, throughout is life. His four children all passed away young, two as babies and two during toddlerhood. His wife also passed away of cancer. Two years ago, during a particularly robust bout of full blown cancer, he prepared himself for dying and bequeathed his house to his brother. Abraham survived the cancer, but found himself homeless upon finally being released from the hospital. He now lives in a tiny, battered shack at the back of his brother’s house, the house that once belonged to Abraham and that he had given to his brother. Abraham used to be a builder and his natural skill is evident in the perfect symmetry of the wall that he is busy building, his bare hands the only tools of his trade.

Mokoena is only 28, but was born with a heart defect. He suffered a stroke at 26 and is now partially impaired on the left side of his body. Mokoena, physically supported by his mother, Ellen, walks 5km every morning from their shack on the other side of Freedom Square location to the building site. For Mokoena life has gained new meaning since he started participating in the building activities. He spent his childhood on the periphery of normal youthful activity. As a result of his weak heart, he could never participate in games and sports with his friends and school mates. Now he is in the thick of things, actively contributing hard labour toward building a house for a fellow community member, while at the same time learning the skills that will enable him to one day built his own house for himself and his mother.

Waldo and Hugo joining building activities in the school holidays; here Mokoena and Abram show them the 'seretse jive' (mud dance).

Waldo and Hugo joining building activities in the school holidays; here Mokoena and Abram show them the ‘seretse jive’ (mud dance).

Abraham and Mokoena both came to be a part of the Qala Phelang Tala building mentorship programme as a result of being out-patients at the University of the Free State’s Occupational Therapy clinic in Rocklands location. Their presence is testimony to the effort and dedication of Heidi Morgan and Bronwyn Kemp to reintroduce their patients back into their communities as fully functional members, able to contribute towards and participate in living a full life.

As for the humble story of my life – well, I was standing in the doorway of Lientjie’s existing shack dwelling and hesitantly introduced myself to the three adolescents inside. They courteously reciprocated and introduced themselves as   Thembeke (18), Lonkululeko (16) and Kenneth (15) and invited me in. We chatted tentatively for a while and I asked about the beads they were wearing. It turns out that they are a trio of aspiring sangomas. The calling from the ancestors runs in their family and each one of their lives is currently a conundrum of figuring out how to heed their calling, appease the ancestors, while still having a normal adolescent life and attend to school and studies. After about an hour or so Kenneth produced a small, vibrantly patterned bag and benevolently offered to throw the bones for me. I cautiously obliged. He asked me to blow three times into the bag. A short ritual ensued of shaking the bag, repeating my name and singing softly. He emptied the little bag on the floor in front of me.

The Freedom Square Shack Replacement crew on site, day 18.

The Freedom Square Shack Replacement crew on site, day 18.

I could not help but be transfixed by the contents that now lay scattered at my feet. Among the bones, shells, beads and trinkets lay four large steel nails. The first thing I noticed was that they all lay with their sharp ends facing away from me. I remember thinking: “that must be a good thing!”. According to my trio of hosts, this was indeed the case. It meant that there are no people in my life who actively wished me harm. As for the rest of the story told by the bones – all I am prepared to say is that it cut disconcertingly close to the bone. However, I somehow doubt that I will consent to having the bones thrown for me again. The prospect of those nails potentially facing me with their sharp ends next time is too dreadful to contemplate. Quit while ahead, me thinks…

Contributed by Amanda de Gouveia on behalf of QPT. Photos courtesy of QPT. Please visit their Facebook page for more photos of the day.

Please see our Disclaimer.

Amanda de GouveiaAmanda de Gouveia has been a research assistant at the Centre for Development Support at the University of the Free State since 2010, where she has mostly been involved in research projects on social development and local economic development. This has refined a unique repertoire of research skills, both qualitative and quantitative. She has also Masters degree in Research Psychology.

Lebone Village launch

Imagine being outside on a chilly Free State winter morning with the sun just coming out and starting to gently warm your body. Now imagine being told to take off your shoes in order to trudge in icy cold mud. I glanced at my fellow volunteers and I saw a collective dissent quietly dawn on our group – this is not what we signed up for!

Mandela day

It was the morning of 18 July, Mandela Day, and we were all gathered at Lebone Village on the outskirts of Bloemfontein to volunteer our 67 minutes for the orphans. We were standing in a circle around Peter McIntosh, who was valiantly demonstrating to us the endeavor of making adobe bricks.

Peter McIntosh demonstrating how to make cob

Peter McIntosh demonstrating how to make cob

The mix using ingredients easily available for the project was chosen after rigorous testing. According to Peter, the mix will differ in every situation, depending on the composition of the ingredients used. The chosen mix for the adobe bricks at Lebone Village was as follows: collect two parts red earth, 2 parts sand with rubble, one part fine sand and two parts water in the centre of large piece of 25” thick canvas material.

Now mix it all into clay with your feet by walking back and forth through the cold, wet mixture. When the cob mixture starts to flatten out, pull the canvas up-and-in towards you from the corners to bring the clay mixture back into the centre of the canvas and into a manageable heap. Now start stepping onto it again. The clay is the right consistency when you can make a ball with your hands and pull it apart into two separate pieces without it crumbling. Adding straw to the mud mixture assures bricks that are well insulated against cold and heat, the more straw you add, the better insulated your bricks.

Adding water

Adding water

Adding straw binds everything together and adds insulation value

Adding straw adds insulation value

Lots of people turned up

Lots of people turned up

 

While the majority of us were still apprehensively contemplating the prospect of braving the cold and mud with naked feet, one person rose to the occasion without hesitation. In the spirit of “first being a follower in order to be a leader”, Itumeleng Santo started pounding the mud into clay with some über cool dance moves. Itumeleng is an out-patient at the University of the Free State’s Dept of Occupational Therapy’s clinic at the MUCPP offices in Rocklands location. He is severely impaired due to a brain injury that he suffered during an assault. For Itumeling, taking part in the Mandela Day activities at Lebone Village was therefore also a day of getting therapy without being given therapy. The Dept of Occupational Therapy vision is to support and treat their disabled and impaired patients in such a way that they will be able to return to their families and communities and be able to fully participate in community activities again. The aim is for such patients to become fully functional individuals who can partake in economic activity and contribute towards their own livelihoods.

The MUCPP clinic of the Dept of Occupational Therapy is not only for patient care and therapy, but it also serves the wider community as a place where youth can hang around after school and in this way be kept off the streets. Heidi Morgan and Bronwyn Kemp, who run the clinic, aspire to teach these children skills that will help them to create their own employment upon completing their school careers. Learning how to make adobe bricks and tire pounding for alternative and natural building practices are two such skills.

This notion of self-empowerment of the impaired, disabled and destitute was the golden thread that ran through the activities at Lebone Village on the morning of Mandela Day. Stakeholders from support institutions to the disabled came from all over the Free State region to learn the new green building techniques of making adobe bricks and pounding tires. These are skills that they intend to take back to their home towns and villages, skills that they hope will enable them to become self-sufficient and self-employed, able to earn money and make a living for themselves, without being a burden to their families.

Getting our feet dirty

Getting our feet dirty

Peter McIntosh demonstrating putting cob into the brick mold

Peter McIntosh demonstrating putting cob into the brick mold

With the ice now literally and figuratively broken by Itumeleng, the rest of us started to get into the spirit of the day. The extra brave ones took of their shoes and started pounding cob with their bare feet. The more modest traded their shoes for gumboots to get the job done.

Some started working the cob with their hands. Anita put on some vibey music and soon the day was in full swing. Volunteers started forming little groups, each group working their cob on their own piece of canvas. Some people would collect the pounded cob and compact it into wooden molds set out by Peter for this purpose. These mudbricks would then be left to dry in the sun for several days, where after they will be ready to use for building.

Peter McIntosh demonstrating putting cob into the brick mold

Peter McIntosh demonstrating putting cob into the brick mold

The teaching of green building techniques to the greater Mangaung community also served as the launch of the Lebone Village Climate Resilient Arts, Crafts and Cultural Hub and was initiated by Qala Phelang Tala, a non-profit organization based in Bloemfontein and associated with the Centre for Development Support at the University of the Free State. Qala Phelang Tala is Sesotho for “Start Living Green” and is the brain child of Anita Venter, a researcher at the Centre for Development Support. QPT strives to empower “change agents” through social entrepreneurship in order to create systems addressing housing, food security, water efficiency and energy independence that are resilient to climate change. Their slogan is “Learn by doing!” This means that they not only preach green building and sustainable, environmental friendly living, but they also practice, implement and teach these techniques. QPT head hunted and hosted Peter McIntosh from Natural Building Collective, who is one of only a handful of natural building experts in South Africa. His experience in sustainable living practices includes sustainable agriculture, off-grid energy systems and an array of natural building techniques, all of which is in fruition on Berg-en-Dal outside Ladismith in the Klein Karoo, a farm owned and managed by the community and educational non-profit the Klein Karoo Sustainable Drylands Permaculture Project, where he is a resident and member.

Some of the mudbricks that were made on the day drying in the sun

Some of the mudbricks that were made on the day drying in the sun

Contributed by Amanda de Gouveia on behalf of QPT. Photos courtesy of QPT. Please visit their Facebook page for more photos of the day.

Amanda de Gouveia

Amanda de Gouveia has been a research assistant at the Centre for Development Support at the University of the Free State since 2010, where she has mostly been involved in research projects on social development and local economic development. This has refined a unique repertoire of research skills, both qualitative and quantitative. She has also Masters degree in Research Psychology.