How to Build a Block Oven

Set the cement blocks on the ground in two rows of three blocks each, to form a rectangle that is two blocks long by three blocks wide. Each block should touch the blocks next to it. Set them on bare ground, sand or stone, in order to avoid the risk of a fire.

Cover the tops of the cinder blocks with bricks. This should take 24 bricks. These bricks will help absorb heat and hold it in longer.

Set the flue on the base of the oven that you have constructed. Center it so that a gap of a few inches lies between either end of the flue and the edge of the base.

Make two walls of bricks on either side of the flue. Stack them five bricks high and three bricks long to completely cover the sides of the flue. They do not need to be mortared together. This allows you to easily take the oven apart if you want to move it, rebuild it or just put something else in its place. It also allows the smoke from the fire to seep out between the cracks instead of constructing a chimney, simplifying the project immensely.

Make a third wall of bricks at one of the ends of the flue, to make a back to the stove. It, too, should be three bricks long by five bricks tall.

Cover the top of the flue with bricks to make a thick roof to the oven that will hold in the heat. Two layers of bricks on top of the flue will bring the roof up to the tops of the walls. This should take all of the remaining bricks but two. Use these two bricks to control the draft, the amount of air getting into the oven. Place them over the open end of the oven to reduce the air reaching the fire, remove them to maximize the airflow.