On a flat, stable surface, mount two support legs using 15-cm cement blocks and lay a reinforced concrete slab 10 cm thick.

Prepare a 2- to 3-cm-thick layer of lean mortar on which you mount the oven floor, verifying that it is perfectly flat.

Mount the oven without mortaring the joints.

Build a wall around the oven using 10-cm cement blocks. Do not use cellular concrete. Mount a flue with inner dimensions of 20 cm x 20 cm.

Surround the oven with a layer of rock wool 5-10 cm thick, then cover it with about 10 cm of sand, or apply expanded concrete without rock wool.

Build a roof over the oven and add the desired trim.