Firebricks are extremely solid and sharp edged, they can be butted up against each other with no gaps in between, they fit really well. The firebricks weren't just laid onto the vermiculite slab, they sit on a bed of 'fireclay' which is a sort of putty, you can see the tub in the previous photo, and I needed 2 of these tubs, they cost about ?10ea from builders merchants/plumb stores
Join Date: 02.06.2009 Comments: 55
Firebricks laid on fire clay base
Here we can see that I have laid the firebricks onto the vermiculite concrete slab to see how much gap to leave down both sides. The firebrick base is 5x12 (60 in all) firebricks each costing @?2 ea so quite a costly part of the oven.