Nepali for Nepali (NFN) is a non-governmental organization that registered after two major earthquakes struck Nepal in April and May of 2015. Almost 9,000 people lost their lives and 590,000 homes were destroyed leaving millions displaced. Tragically, a large percentage of deaths could have been avoided if buildings had been constructed in a safe, earthquake-resistant manner. Lying on the meeting point of the quickly converging Indian and Eurasian tectonic plates, it is expected that Nepal will face more large-scale seismic movement in the future. Nepali for Nepali aims to introduce a new building technology to greater Nepal that will prevent such disasters from having such a huge impact again.
Interlocking Blocks are a construction system that has proven to be resistant to earthquake damage. The blocks each have a male and female part which interlock when stacked horizontally. This increases the stability of the building. Unlike brick construction which is extremely vulnerable to seismic movement, interlocking blocks resist both vertical and horizontal movement. Not only do they interlock, the blocks also have holes through which rebar can be placed with mortar for reinforcement. This technology requires the use of a single hand-press block machine which uses a mixture of cement, soil, sand and water to compress into interlocking blocks. These machines require only manual force to operate; extremely suitable for Nepal which suffers frequent electricity cuts.
Interlocking Block production begins with collecting the necessary material: soil, sand and water. To this mixture a 10% amount of cement is added. This combination allows the sand to bond with the cement while the soil content creates the bulk of the density. To form the Interlocking Blocks, this mixture is then placed in one hand-press Interlocking Block machine. The machine has one mould into which the mixture is placed and compressed into a block. The compressed earth block should then be placed in a covered area to begin the last stage of production.
Curing the blocks typically requires a 21 day period. The blocks are kept under cover in a cool place for 3 days and then moved outdoors into direct sunlight. Meanwhile, the blocks should not be allowed to fully dry for 7-10 days. This requires applying water to the blocks twice a day for the first week. Once the blocks have set in water-intake, they should be placed back under cover for another 11 days.
Benefits for Nepal:
- Environmentally friendly – zero emission
- Use of local resources – soil, sand, water and other building materials can be found locally
- Low-cost housing – maximum use of local resources and minimum use of cement products such as: mortar and plaster
- Process is all on-site – from block production to building construction
- Use of local manpower – supports local laborers
- Easy-to-learn construction – unskilled laborers can easily be trained
- Fast construction – each home can be completed in less than a week
- Natural heating and cooling – soil and sand base make the blocks thermodynamic
Nepal Government Approved Catalogue of Earthquake Resistant Houses
For more information on interlocking block technology, below is the government approved earthquake-resistant building methods. The catalogue was produced by Nepal’s Department of Urban Development and Building Construction in March, 2017.