Completed in 2019, Nepal’s first strawbale house showcases an earthquake shake table tested straw bale wall system costing about half the price of a conventional earth-quake resistant buildings. The lime and clay plastered straw bale walls provide super-insulation, moderating extreme temperatures, while the breathable clay and lime plasters prevent moulds and moisture build-up inside and durable lime render gives a water resistant external layer. Local people were trained in these easily replicable building systems while also using traditional Nepali building methods and local, affordable and sustainable materials.
In April and May 2015 Nepal was struck by two devastating earthquakes, killing 9,000 people and leaving hundreds of thousands homeless. In response, Builders without Borders looked for a test case site to promote and assess the appropriateness of strawbale buildings as earthquake resistant homes in Nepal.
They found the Kevin Rohan Memorial Eco Foundation (KRMEF) in the Kathmandu valley, which already included a showcase of eco buildings. Close to Kathmandu the KRMEF centre was well placed to be a showcase for wider interest, was within the earthquake zone and provided access to a local network of skills and materials.
Some of the other eco-builds at KRMEF are earthquake resistant made from stabilised earth blocks and recycled bottles sat on foundations supported by rammed car tyres, described by the then DFID Humanitarian Shelter Advisor, Magnus Wolf-Murray as, “some of the best examples of low cost earthquake resilient buildings in Nepal."
KEEPING IT LOCAL,
KEEPING COSTS LOW
Using local labour, materials and sharing skills with local people who worked alongside and in leadership roles meant this durable, safe, regenerative building was easily affordable. PAKSBAB (the organisation promoting straw bale building as an earthquake resilient option for Kashmir, Pakistan) estimate building costs to be about half of the cost of conventional earthquake resistant buildings. The addition of lime-stablised soil render has given the building a durable breathable finish and trained local women to continue the maintenance of this building and others.
WHAT MAKES THIS REGENERATIVE?
IMPACT ON PLANET
Low carbon build using locally sourced natural materials which cut down on transportation impacts.
Natural materials reduce pollution from building materials
Passive ventilation, heating and cooling with super-insulation allow buildings to be comfortable without air conditioning.
High thermal performance achieved without the use of energy-intensive, sometimes toxic, industrially manufactured insulation materials.
Natural finishes avoid the environmental and health burden of VOCs.
Little waste creation and bio-degradable, compostable building at the end of life.
Cradle to cradle standard - transformative system with a positive impact on people and planet.
IMPACT ON PEOPLE
Local gardeners, mainly women trained into leadership roles for Lime Stabilized plastering.
More affordable than other building techniques, including other earthquake resistant building methods.
From all global shake tests, its been repeatedly evidenced that strawbale buildings can remain standing through earthquakes, so portentially preserving life, shelter and livelihoods.
Lime rendered straw bale buildings promote healthy air inside them because they are non-toxic and breathable.
Lime or clay plastered straw bale walls will moderate temperature extremes through high insulation values and high thermal mass so increasing thermal comfort.
Community capacity building through Increasing skills and income. Through training and use of local labour, people are empowered to build durably with straw and lime, going forward they are able to maintain their buildings and implement future projects.
Comfortable, high performance culturally appropriate buildings provided as a resource for the community.
COMBINED REGENERATIVE IMPACT
This building system with a cradle to cradle design is a transformative system with a positive impact on people and planet. It combines both climate change adaptive and climate change mitigation technology.
DISASTER RESILIENCE - FLOOD & EARTHQUAKE
The combination of the uniquely appropriate resilience of straw bale buildings to earthquakes and of lime-stabilised soil to flood or monsoon damage, promote the possibility of a fully integrated disaster risk reduction solution for areas of high flood, monsoon and earthquake risk.
Integrated systems of training local labour and of local materials use maintains and builds resources and resilience within the area. Local farmers are paid for straw, soil is dug from the foundations and used for free, labourers are paid for their work and women and men can be trained in new trades and skills, building community capacity and livelihoods.
Partnering with an established local organisation gives access to an integrated network of sources of skilled labour, students and self-builders for training, materials availability, cultural insight and skills transfer. It allows projects to be inclusive and empowering and increases the learning of both the external trainers, organisations and local communities.
For earthquake resistance, PAKSBAB have completed 40 strawbale homes in Pakistan through training of trainers in seismically vulnerable northern Pakistan using the same load-bearing wall system, proving upscaling of skills and production is possible.
For flood and monsoon-rain resilient buildings, UK Aid funded Strawbuild training has led to the building of over 200,000 lime-stabilised soil houses in high flood-risk areas across southern Pakistan. Training in lime-stabilised soil can quickly equip diverse groups to become proficient in building resilient houses in their local, vernacular style, often predominantly of earth, that remain stable (do not dissolve) in water. All earth building elements can be stabilised with small amounts of lime - including foundations, wall blocks, mortars, floors, renders, plasters and roof screeds - so skilled labour and production through training can rabidly be upscaled.
Strawbuild have authored a manual in Lime Stabilised Construction - a practical guide to spread best practice with engineers, masons and self-builders, as used in the training courses for many NGOs and International Humanitarian Organisations in the UKAid funded Flood Resilience Programmes of Southern Pakistan - Sindh, Punjab and Balochistan, 2012-2016. The manual is being updated in 2020 to a book to be published by Practical Action.
Lower build costs (by an average saving of 70%) represent an opportunity to build greater numbers of carbon-zero, high performance and disaster resilient houses at the same cost as fewer conventional earthquake and flood resilient buildings.
Straw and Lime Stabilized soil can be used in different combinations and there is scope for further pilot projects and demonstration builds.
Bee Rowan from Strawbuild explains,
“the next step is to continue to develop both technologies into a climatically appropriate and closer design synergy for full disaster risk reduction - from earthquake, flood and driving monsoon rain. Stawbuild and Builders without Borders plan to partner again in the straw-rich but high flood-risk Terai area of Nepal, using light straw, lime-stabilised soil walling systems, another easily replicate and appropriate building method using the same locally available materials for such areas of extreme climate at risk of both flood and earthquake."
Independent, published evidence from IOM (UN's International Organisation for Migration) and ARUP Engineers, London, supports the use of lime-stabilised soil for flood resilient housing and details test results confirming high compressive strengths gained through stabilising soil with lime and the durability of the stabilised mixes in water for prolonged periods. Bee expects to return to Nepal this year (2020) to continue to support and promote these sustainable technologies and to partner local engineering and earth building companies in offering scalable solutions, such as within the design of resettlement villages, schools and community buildings. She is currently advising on similar uptake, design and training in Iraq, KRI (Kurdish Region of Iraq) Nigeria, Nicaragua and India, as well as within the UK.
Plans from PAKSBAB can be adapted to use varied local straws, and bale presses can be made from locally sourced agricultural machinery or timber on site. Once the wall system is in place, other parts of the design can be adapted to suit local vernacular styles, materials and skills.
Lime is a widely available and most cultures have currant heritage use of lime, for example, in an IOM survey of vernacular buildings in Pakistan, 28% of the buildings built between 2010 and 2014 used lime. Following simple soil tests, an accurate formula can be found for all local soil types to make durable renders, plasters and light straw lime stabilized soil.