Q&A

Building with earth, straw, wood and manure

As many of you are asking important questions about our project and our construction techniques, we summarize some of the answer we have already given. As more questions will come up, we will add them here so everyone could find what he/she is looking for. However, if you have more questions, please don’t hesitate to ask and we will be happy to answer you as we can.

What means TezekEvleri?

TezekEvleri means dung’s house. Of course our buildings are not entirely made out of dung, in reality even very few of dung is used especially in earth plaster and earth bricks. However, the name comes from the project main purpose, using local and natural materials in a durable and easy way, preventing soil degradation and resources over usage. In this way, dung – associated to earth and straw – is a good material as it stabilizes the plasters and the bricks, but also enriches the soil is the buildings are abandoned and let to decomposed.

What materials did we used for the construction of the buildings?

We mostly (but not only) used natural materials such as earth, straw, wood, sand, gravel with different techniques. But as any modern buildings, we used also glass, metal, ceramics and plastics as they are difficult to avoid. As binder we used mostly clay, but also lime.

Which techniques did you used for the construction of the buildings?

We used several construction techniques and mostly mixed several techniques in each building as it is more efficient to use materials and techniques according to their properties.

  • As foundation, we used gravel bags, meaning we fulfilled polypropylene bags with gravels and then stamped them into trenches.
  • As walls, we used straw-bales (load-bearing technique), slip-straw (light straw-clay) inside a wooden frame and also as external wrapped insulation, mud-bricks (load-bearing technique with main and half bricks), earth-bags (load-bearing technique)
  • As structural elements, we used wooden frame or straw-bales, mud bricks or earth bags.
  • As roof heat insulation, we used straw-bales or slip-straw.
  • As plasters and finishes, we used earth plasters reinforced with cow-dung, casein, linseed oil, egg white; lime plasters, tadelakt, clay paints, burned clay plasters
  • As floors, we used earth floors (rammed earth floors and adobe earth floor) protected by linseed oil or tempera (linseed oil, pigment and yolk)
How did you choose the techniques that you used?

The techniques were chosen according to the design of the building, the properties of the materials and the function of the building elements.

Where insulation was needed we used straw-bale or loose straw and very light slip-straw as they are good insulation materials (λ<0.7W/Km²). Where we were needing high thermal storage materials, we used mud-bricks, heavy slip-straw or earth-bags. Earth plasters and earthen walls were also used to regulate the humidity level in the buildings.

 Straw-bales were also used for sound insulation. Cob, a plastic earth material was used for decoration and aesthetic purposes.

As plaster, we used earth plasters stabilized with flour paste in the interior and we try different techniques for the exterior plasters to lessen the yearly maintenance. Where waterproof plaster where needed we used tadelakt (a Moroccan lime based plasters) and lime plaster while burned plasters and oiled clay paints were used for water resistant surfaces.

Are the buildings resistant to weather conditions?

After 3 winters, we can tell that our buildings are resistant to normal rains and snow as well as heavy sun and droughts especially thanks to the large roof eaves and drainage in the foundation. However, as the winds are very heavy in the area, earth plasters are not fully appropriate and we are experimenting every year a new technique to stabilize the plasters and protect the walls.  But no walls have fallen of nor any water entered the buildings.

Are the buildings resistant to earthquake?

As our buildings are made with not conventional materials and technique, no regulation in Turkey deals with and even few international regulations are taking it in account. However, while building it, we were following the ICC-IRC 2015 – Appendix S and R (International Residential Code for USA) for straw-bale and slip-straw and the NZS 4298 and NZS 4299 (New-Zealand Standards) for earth construction. So yes, our buildings are resistant to “normal” earthquakes as any other modern buildings. Moreover, all the materials we used can be used as infill materials inside a structural wooden or steel frame which would make the building compliant to earthquake codes. The main advantage of using these materials is that even after an earthquake, the house can be repaired or rebuild easily, using the same materials whereas a concrete house will need to be put down.

Are the buildings resistant to fire?

Most of the materials we used are not flammable materials or materials that burn with difficulty. As straw-bales are very compact, it is difficult to burn and then we also protect them with an earthen plaster. Other materials are made with earth, making them very difficult to burn as earth is not a flammable material. The timber used in the construction for structure and surface is the only flammable material that can be easily accessed and then again, it is not easy to start a fire and it is burning slowly enough for the inhabitant to be safe out of the building. As we used very few plastics are used, fire would not spread fast and no toxic smoke will be released.

Are insects, birds and other rodents entering the buildings?

As in other farm building or buildings in rural area, insects and rodents might occasionally enter the building and nest for the winter. However, as there is no food easily available for them in the wall or the roof, they will not prefer to stay and especially not in the wall because of its density and difficulty to dig in, in the opposite of light and modern insulation such as Rockwool or Styrofoam.

Are the buildings healthy and comfortable?

The usage comfort of the building is depending of the design and user of course. And to make the building more comfortable and energy efficient, we designed it according to bioclimatic principles.  But the physical comfort (heat/cold, humidity level, noise, smell…) is mostly depending of the materials used as is the “healthiness” of the buildings. As no chemical materials are used (paints, plastics and PVC, glues…) very few VOC (Volatile Organic Compounds) and formaldehyde are released in the air, limiting the impact on the health of users. Moreover, as we are using “breathing” materials such as earth plasters, straw-bales or earth construction techniques, the humidity level in the building is regulated through humidity circulation through the walls and humidity storage in the plasters which makes the building more comfortable. As we used heavy materials, we also managed to put a very high thermal mass in the building which regulate the temperature both in summer and winter, preventing overheating and overcooling.

How can I do such building in a city? Can I build it on my land? How big can it be? Can you help me with it?

Yes, you can use such materials and techniques, both in urban and rural area. Examples of large and small buildings exist both in Turkey and abroad. The highest straw-bale building is in France and is 8 storeys high in a city and the oldest is in USA and is more than 100 years old. The first straw-bale building in Turkey has been built in 1999 and then more than 50 of them have been done. Earth buildings have been made since centuries and modern construction techniques only make it safer, faster to build and more comfortable. Examples of them are found across any cities on all continents.

The new challenge is to design an energy efficient building adapted to modern life conditions and respecting the building rules of Turkey. And for this we can help you we our knowledge of the different techniques and of energy efficient design. You can either participate to some of our courses or workshops to learn by you-self how to do or hire us as a consultant to help you on your design and construction process.

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