Fire-proof and earthquake-resistant construction testing using clay and rice husks

Prefabricated Straw panels - fire & earthquake resistance testing
strawbale panels, clay cladding
15.07.16 to 17.07.17

Using natural, renewable and locally available materials is the ideal solution for increasing community resilience, reducing costs and the environmental impact that shelter construction can have. However, with the increase in natural and man-made disasters, this more beneficial form of building must also be able to withstand the harshest of threats to further increase local resilience.

Ensuring the safety of natural building materials is of paramount importance, not only to encourage their use and adoption at the community level, but also to provide evidence to government authorities, iNGOs and funders that these techniques are able to meet some of the challenges affecting their beneficiaries.

Through a joint initiative between Tamera, Terrapalha Architects and the ITeCons Labs at Coimbra University, financed by Portugal 2020, it has been able to do a series of safety tests on prefabricated strawbale panels composed of rice straw, clay and wood. Of special interest were the results relating to fire resistance. After 120 minutes of fire, the test came to an end and the walls still kept their structural integrity.

In comparison to other building materials, strawbale and their prefabricated panels offer good levels of sound insulation, thermal insulation, fire resistance and moisture control, especially when plastered in thick clay or lime plasters. Straw is available as a surplus in most grain-growing regions in the world and can be baled through machines or simple mechanical presses. Strawbale construction can be taught locally and does not need special skills. Strawbale panels can also be manufactured locally or on-site.

Strawbale construction is a low-impact form of building, besides using little energy during the construction phase and saving energy during its use phase, the straw also sequestered CO2 while growing which then gets stored in the walls during the life of the building. At the end of its life, the materials can be safely returned to nature.

In July 2017, after one year, the research partnership between ITeCons and Tamera, the Peace Research Centre in Portugal - founding member of the Blueprint Alliance - came to an end. Blueprint core member Christoph Ulbig and other collaborators at Tamera built a series of prefabricated prototype walls, which were tested at the Tacnalia Institute in Bilbao for fire resistance. At ITeCons, the testing included fire reactivity, thermal conductivity, water vapour transmissivity and resistance to other climate influences.

Christoph and Catarina Pinto (Terrapalha), project coordinators, state that only a short thickness of clay plaster is enough for the strawbale walls to offer lasting durability and superior comfort. A strawbale construction can offer up to three times more fire resistance than constructions using synthetic materials.

The budget for the research project was €20,000. The European Union programme, Portugal 2020, supports this research project which aims to increase the evidence for strawbale building, as well as increase public and technical recognition. The tests carried out on fire resistance and other common safety characteristics as per ETA (European Technical Assessment) will allow for large scale production and construction with the prefabricated panels.

For further information:
VIDEO of the PAKSBAB showing an earthquake test done in 2009 in the USA for houses to be built in Pakistan after the 2005 earthquakes
VIDEO of Affordable earthquake-resistant homes in Pakistan with hand-pressed strawbales.


Catarina Pinto, Terrapalha arquitectos
Moritz Reichert, Dobry Dom, Polónia
ILOS Tamera
Itecons, Laboratório de engenharia da Universidade de Coimbra
Tecnalia, Laboratório Bilbao
FASBA, Associação Alemã de construção em palha
Relatório do ITECON

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