As you can imagine, it is especially important that the roof of a backyard oven be fireproof. Said roof also needs to stay in place without screws or staples, since there is no wood to attach them to and it is hard to put those things in cement. Lastly, it needs to be made in units light enough to maneuver to the top of the oven, but heavy enough to sit firmly in place!
Greg made five long cement tiles for the roof of our backyard brick oven. A form was made out of plywood so that the 4 side tiles would have an “L” shaped lip on one edge. The form was the same for each of the bottom two tiles. However, the top tiles had to accommodate the slightly asymmetrical roofline, as well as fit around the chimney stack.
The cement was mixed with vermiculite, to make it lighter in weight. It retained the natural light gray color of cement, as opposed to the cement which had cinder added and looks darker even when cured. Each tile had a piece of chicken wire placed laying across its whole surface horizontally, midway through the cement pour. The added stability to the cement was even more crucial since the tiles are only about one inch thick.
A brace for the roof was made of rebar welded to the outer wall rebar, before the top of the outer wall was poured. A cement triangle was poured around and attached to the rebar to provide additional support at the midline of the roof, from side wall to side wall. The tiles were lifted and carried on edge, to avoid cracking.
The two bottom side tiles were put in place first, with the “L” lip set firmly in the notches in the front and back walls of the oven. There are also notches in the cement triangle in the center. Next, the top side tiles went on, but only had notches in the back wall and center triangle. Thin metal flashing is bent to cover the gap between the tile and the chimney stack. It screwed fairly easily in to the cinder cement, but is just resting on the roof tiles. (this can be seen well from the side in the top photo) A final, narrower cap tile covers the very top of the roof line to finish the roof.
Now, the insulation cinder space is safe from collecting any number of things. Like squirrels and birds. Wouldn’t want any unexpected roasted baby squirrel…. Along with the roof being fireproof, squirrel, and bird proof, rain water drips right off of it and snow glides to the ground. If those roof tiles were a little easier to make, I would ask for some for my whole house! :-)