Roof Cob Oven

About 2 parts sand to 1 part clay.

Roof cob oven. You would place a bond beam at the top of the cob wall ideally concrete and rebar or alternatively airplane cable connecting all the members of the roof in one big circle. When you bake something like bread in an oven it releases an enormous amount of water vapor as it cooks much of which is absorbed into the oven wall. This cob oven was built leading up to the 2008 forest festival held in jackeys marsh tasmania. Load up your wheelbarrow of sand and dump it in the middle of the tarp.

Use your hands to carve out a small depression in the middle of the sand pile. The interior ceiling height should be around 75 of the interior oven floor s diameter and the door height should be about 63 of the ceiling height. Cob ovens are a relatively inexpensive way to bake with all the benefits of wood fire such as a hot hearth. Pour off the water from 3 buckets of clay and dump the clay into the sand pile.

The oven i will propose and outline below is a highly insulated cob oven. You mix those two together so that they re very well mixed. Materials are raw and often sourced locally from the land. However i wouldn t recommend either of them for an oven.

Sand about 30 40 gallons to fill oven s base and to put in cob as needed sand can often be found by bodies of water or collected from construction sites like subsoil. Lay out a recycled lumber tarp at least 6 x8. They way the roof is designed is to act in compression while exerting force on the bond beam which will act in tension. Lime wash creates a somewhat weather resistant surface but doesn t fully replace a roof.

Any smaller and you won t have good heating or a large enough cooking surface. Straw one bale to make cob make sure you do not confuse straw with hay. The smallest cob oven interior size that we ve heard of is 16 floor diameter. The oven is a design from build your own earth oven by kuko denzer.

The inner most layer of mud or cob that we re going to put on our oven is just sand and clay. Building the base for your cob oven the base of the oven would be constructed of 8 wide concrete blocks 8 x 8 x 16 so the concrete base needed to be 16 wide to provide a solid footing. When dry cob is extremely hard and durable and highly capable of storing heat given enough insulation the focus here is of course building with natural and recycled materials whenever possible. I m not in the construction trades.