BUILDING WITH PUMICE: Making blocks out of pumice, lime ...
· With a little practice and skill, pumice concrete cavity blocks are also easy to make in small quantities. The size of the wooden mould is more or less a question of personal preference, but a 49 — 24 — 15 cm format with two cavities is recommended (Fig. 31). With a view to facilitating placement of the blocks, it's advisable to leave the cavities open at one end .