In article
Ian Stirling wrote:
Chris Bacon wrote:
meow2222 wrote
Finally you can make your own concrete blocks if you want, need a
simple wood frame on a flat sheet, line it with polythene, and pour in
load after load. A 4x8 mould is 2 m^2 or so of blocks, so with 9"
blocks you can work out what you'd save.

Why make blocks when you can cast whole walls in stages?

Why cast walls in stages, when you can cast walls in one?

Because you need a lot less shuttering if you do it in stages.