DIY Wood Brick Oven

Choose a location for your oven that will not be subjected to passing traffic, because the exterior will be extremely hot when in use. Site the oven away from children’s play areas, footpaths, vehicle parking areas, overhanging trees and structures.

Create a concrete base slab approximately one foot larger all around than the external dimensions mandated by the instructions supplied with your kit or mold. Mark the project area with stakes and stretch string between the stakes. Use a shovel to dig out the enclosed space until all surface material such as grass and flower gardens are removed, then frame the space using 4-inch forms. Remove the stakes and strings. Install a rebar grid for reinforcement, pour in concrete and level off across the tops of the forms. Allow to fully cure, then remove the framing.

Build three concrete block walls to waist height on the slab. The outer two should be on either side of the slab, running front to back and stepped in 6 inches from the edge, also leaving 6 inches clear at both the front and back. The third wall should be in the center; it, too, should have 6 clear inches clear between both its front and back and the edges of the slab.

Cut a sheet of concrete board to the size and shape of the top of the walls. Use a high-heat-resistant construction adhesive or mechanical fasteners to secure the sheet in place. Allow adhesive to cure if used.

Repeat the process of building framing with forms, this time tight to the outside of the sheet of concrete board and 4 inches deep. Pour an insulating mix of vermiculite, cement and lime into the center of the shuttering, spreading it out to within 4 inches of the forms and making it approximately 1 inch deep. Pour a second concrete slab; this will be the oven’s hearth. Allow to fully cure, then remove the framing.

Mark a shape on top of the hearth using dark-colored chalk, six inches inside all its external dimensions. Given the 1-foot over-sizing of the first slab and 6-inch over-sizing of the second, this marking should accurately describe the desired shape and size of the oven. Fill the shape with firebricks laid on their backs; if the hearth is slightly uneven, bed them into the thinnest layer of builder’s sand necessary to compensate.

Assemble your kit or mold above the layer of firebricks, following the manufacturer’s advisements and instructions. Full kits and molds that act as temporary supports, first cloaked in firebrick and then removed, are available from specialty suppliers and often can be purchased by special order through a local builder’s merchant or home improvement warehouse. Those outlets should be also able to provide all the ancillary supplies necessary to complete the project, such as the firebricks themselves.