Floor of the white bake oven

I’m on the 15th coarse of our masonry heater core plan, which is the location of the floor of the bake oven above the fire box. We are unsure when the tiles get installed and if they are mortared in? In drawings of later courses sometimes it is shown there, sometimes not. Is there a gasket around it or are those just 1/4 spaces around it?

You can set them at any point after you have put in the supports and begun the side walls.
They should not be mortared but rather float, surrounded on the bottoms and sides by 1/4” ceramic paper gaskets. These oven floor slabs receive the heaviest thermal cycling because of their position. They must be able to expand and contract and, if necessary, be able to be replaced.

How about the gaskets, do you like to mortar them onto the side and bottom bricks?

@dclaire, yes, I like to put some dabs of refractory mortar between gasketing and firebrick so they don’t move around.