Does anybody have experience building in Thailand with rubble trench foundations? I'm not a builder but this looks like a good way of saving on concrete. My sub-soil is pretty much pure kaolin so although it's clay, it's non-expansive. As far as I can tell from hunting around on the internet, this should be OK - and if it's good enough for Frank Lloyd Wright it's good enough for me - but any experience/advice would be gratefully received.