Low-cost, rapid-building systems for West Africa

I am not sure there is any time saving but if you are interested in reducing costs you might want to consider construction methods using mud-bricks (adobe) or cement stabilised bricks (banco stabilisé) promoted in West Africa by two NGOs - Woodless Construction and Voutes Noubiennes. Also by ESIAU (école supérieure d’ingénierie d’architecture et d’urbanisme) in Bamako www.esiau-mali.com and www.esiau-mali.net Contact the Director Abdoulaye Deyoko (email) : esiau-infos@esiau-mali.com.

There are many examples of buildings built entirely in these materials and also examples where they are combined with more conventional concrete construction techniques, to reduce costs and improve thermal qualities

Usually to save time you increase cost, or to save cost you increase time. But it depends on what you mean by reducing time - do you mean construction time, or time to go from raw product to finished building?

Compressed Earth Block (CEB) is a modern refinement of the more traditional adobe earth block system, and some CEB systems, once you have the blocks, can be used to very quickly build a house. One system I have been especially impressed by now use the name StarTop (startop@blockprasan.com) the company is based in Thailand. The biggest catch with this type of system is that it is really important to get the foundation flat - because the system doesn't use mortar, so there is no room for error.

Dear Femi,

Can I suggest that, unless you are under a big time constraint (such as emergency relief), "fast" construction is not necessarily a good idea, especially as you then only make savings on labour time. How fast you need to go largely depends on your financing (if doing rental housing, when tenants can move in; if doing ownership housing, when loan reimbursements need to start). A lot of "quick building techniques" are advertised by Northern companies, but are often poor ideas (inappropriate materials, poor durability, high initial cost in machines...)

On cheaper materials, there are many options, a lot developed in South Africa. Some publications by Skat.ch give an overview of possible materials (see "Building Material Leaflets" and "Appropriate building materials" on this page).

Compressed earth blocks can be good idea, but only if you can find suitable soil. The curing time is actually longer than for many concrete blocks, so to have a speedy construction you need to have an efficient workflow and build one house after the other in a nice flowing sequence. GTZ has a production manual for these, and there is a comprehensive guide by the CSIR in South Africa.

And then, remember that housing is only a component of settlement development (infrastructure, services, social components, planning...), which can be another area in which to make savings. I strongly recommend the "Red Book" Volume 1 and Volume 2.

Finally, here are two guides to reduce costs when building, even with usual techniques: Cost management of low-cost housing and Manual of Cost Cuts for Strong and Acceptable Housing.

Happy building,

Rémi