Tutorial on Building a Natural Earth Oven

Build on the Ground or on a Base

• You can build an earth oven on the ground or on a base. If you build it on the ground, ensure that the area is level before starting. A base should be about waist high. Concrete cinder blocks work well as a base, though you can use old concrete, rock, metal barrels, slate or other nonflammable materials. In addition, earmark some space for counter areas next to the oven.

Placement

• Locate it away from anything flammable and have a working fire extinguisher close by at all times. You'll want it convenient to the backdoor of your house and your outdoor eating areas. Think about prevailing wind direction during the season you'll most often use your oven. If it's during the summer and winds blow from the south and west, position your door so the fire is sheltered from the wind. Finally, check any local building codes or neighborhood covenants.

Materials & Size

• To build the oven, you'll need sand, clay and fire bricks. You'll also need a wheelbarrow to move sand and clay, a tarp for mixing the materials, buckets, a tape measure and sculpting tools to form the oven. For size, think about what you'll be cooking in your oven. Generally, a couple of feet wide, tall and deep should be enough.

Building the Hearth

• Whether you use a base or build your oven on the ground, the setup is the same. Firebricks form the hearth and need to sit perfectly level on a layer of sand several inches deep, flushed tightly against each other. Leave a lip or work area just outside where the door will be (for staging the fire and food before inserting them into the oven). Mark the center of the hearth, then draw two circles, with one being 3 or 4 inches inside the first. These circles mark the thickness of the walls.

Form the Interior

• Create a mound of wet sand in a symmetrical dome shape, using the inside circle you marked as your guide. This wet sand will create the cavity of your oven. The measurement to the top of the interior sand form should be several inches more than the floor's width. Moisten sheets of newspaper and cover the entire sand dome.

Mixing the Exterior Material

• Dig below your topsoil to find clay. Spread the clay out on a tarp to mix it using your hands or bare feet, adding sand and water as you mix. Use playground sand purchased from a home center. The exact ratio of clay to sand will depend on the clay you have to work with. Do not use too much water. You’ll know the clay is ready when you can pack it into a hard ball, drop it from chest height and it still holds together.

Building the Oven Exterior

• Cover the sand dome with a layer of the adobe, 3 to 4 inches thick. Use the outer circle you drew as the guide for your outside walls. Use the width of your hand as a guide for thickness as you move up the mound of sand. When finished, cut a doorway wide enough for the largest item you plan on cooking. The height of the door should be about one-half to two-thirds the height of the oven.

Removing the Sand

• Allow the adobe to dry for a couple days, then carefully remove the sand with a trowel. You don't want to damage the interior walls. Once the sand is gone, you can speed the overall drying process by building a small fire within the oven.