Wall layout and ash collector

The ash collector is a opening to the fireplace below. The function is described in the section "Living with the oven". The picture shows the layout of the walls. The oven is built from the inside out. The fire bricks are laid dry, supported with the layer of red bricks, separated with the tinfoil. (right) The next layer of bricks creates "ribs" with space between the outside wall and the inside, which is later on filled with insulation.