Building Hope with Lime-Stabilised Soil: A Resilient Solution for Shelters in Cox’s Bazar Refugee Camps
In the world's largest refugee settlement in Cox’s Bazar, Bangladesh, over 1.2 million Rohingya refugees live in shelters made from bamboo and tarpaulin that struggle to withstand monsoons, floods, and devastating fires. An innovative project led by Strawbuild’s Bee Rowan, supported by Re-Alliance, has introduced Lime Stabilised soil as a resilient, low carbon and cost-effective solution for shelter building, which has been approved for use in the camps by the Bangladeshi government.
What is Lime-Stabilised Soil (LSS)?
LSS is a low-carbon, cost-effective building material that combines soil, lime, and local pozzolans (like rice husk ash or burnt brick dust) to create a durable, fire-resistant, and flood-resilient material. LSS can be used as a plaster over a structural frame, to form load-bearing bricks and blocks or as mortar between blocks. Most regions have local sources of lime, pozzolans and soils with a clay content, so unlike concrete, LSS can be produced locally, making it both affordable and more environmentally friendly. In contrast to cement, lime is not heated to extreme temperatures, giving it a far lower embodied energy with low to neutral associated carbon emissions.
Training and continued monitoring key to quality
Building with lime needs investment in training and continued mix testing, meaning that it can take longer than building with cement. Durability is only assured when care is taken to test each mix and tailor the ratios needed to the specific ingredients used. When built with the right care and attention lime buildings can last thousands of years, such as in ancient Roman lime masonry still standing today.
Lime can be mixed with soil to make resilient renders, plasters, bricks, blocks and mortars (c) Bee Rowan
The Pilot Project in Cox’s Bazar
With a £7,000 grant from Re-Alliance, the pilot project tested the feasibility of LSS in the camps. Working alongside engineers from the International Organization for Migration (IOM) and Rohingya refugees, Bee Rowan conducted testing to identify the best soil-lime mixtures for local conditions. The results were positive.
Monsoon & Flood Resilience: LSS test mixes showed high compressive wet strength meaning it has the potential to withstand heavy rains and flooding without deteriorating. Adding LSS to the tarpaulin roof panels offers a durable waterproof cover for shelters.
Fire Resistance: Following a devastating fire in Camp 11, fire tests were conducted on LSS-coated bamboo shelters. The results were staggering—while a traditional shelter burned down in five minutes, the LSS-plastered shelter remained intact even after 20 minutes of intense flames.
Thermal Performance: The piloted LSS shelters provided much-needed insulation, keeping indoor temperatures significantly cooler during extreme heat waves.
Involving the community: Although building with lime needs attention to detail and a closely followed process, it is not overly technical or complicated. This enabled community participation from Rohingya women and men, some of whom had past experience of plastering their homes before fleeing conflict.
Scaling Up: A Major Breakthrough
Thanks to the pilot's success, the Bangladesh government approved a pilot for IOM to build 50 LSS plastered shelters and LSS stabilised paths and steps. The shelters have performed well, leading to additional funding for IOM to build over 2,000 LSS shelters as firebreaks across the camps. This is the first time LSS has been used at such scale in the camps and the hope is that quality practices can be maintained despite the pressures for volume building on a tight schedule.
The future for LSS Shelters in Displacement settings
With growing interest from other organisations, LSS has the potential to be used worldwide for shelters built following disaster and displacement. It has already been successfully used in Pakistan and Nepal, for reconstruction of homes destroyed by flooding and earthquakes showing that LSS is an adaptable material which can be used in many adapted vernacular designs. By reducing reliance on expensive and unsustainable materials, it offers a practical, scalable solution for safer, more resilient shelters in crisis-affected communities.
Training key to success
One of the key factors in the successful implementation of LSS is hands-on, in-person training. By engaging local engineers and communities directly, trainers ensure that knowledge is effectively transferred and adapted to the specific needs of each community and environment. While most soil types can be stabilised with lime, it is vital to get the right ‘recipe’ for each unique soil type and lime and pozzolan source. It is important that both donors and implementers understand that building with lime takes time and investment in monitoring mixes to ensure quality. To accompany training, Strawbuild and IOM have produced a guide to Lime Stabilised Soil building, available at: https://www.scribd.com/document/663893347/Lime-Stabilized-Construction-A-Manual-and-Practical-Guide
Re-Alliance are working on an online course which will include building with LSS as part of a regenerative shelter module. We are looking for examples of where Lime has been used in reconstruction or shelter provision, so please get in touch to share learnings.
A rare opportunity in a challenging context
New building materials are seldom approved for use in the Rohingya camps, so the government approval of LSS is a rare opportunity coming at a time when the Rohingya people are at greatest risk from aid cuts. It remains to be seen if quality assurance can be maintained in the face of tight deadlines and demands for quantity, but the more that agencies can work together to share learnings and skills and invest in training, the better the chances that LSS can achieve its potential. LSS represents a rare beacon of hope in the most challenging of contexts and could offer the Rohingya people access to shelters that are safer from fires, cooler in scorching temperatures and watertight in the heavy monsoons.
Comentarios