An answer to this is to produce a standard construction kit; which we've dubbed the Dura-San. Water For People worked with John Parry's Associates to produce mortar less block construction system and then refined the idea in Uganda. We first worked with a large materials manufacturing company called Multiple Industries but found more success with a medium sized enterprise called Turn Key. Concrete manufacturers are quite common in Uganda but ensuring that they produce quality products could be a challenge.
The idea is reasonably simple. Concrete blocks are cast and left to cure.