Cob

Cob is a natural building material made from clay, sand, straw, and water.

Main Parts of a Cob House

• Foundation
• Walls
• Roof

Building a Cob Foundation

Rubble Trench

• Dug below the building perimeter for drainage
• Filled with gravel (drain rock)
• Includes perforated drainpipe
• Sloped bottom for water runoff

Stemwall

• Stone: natural look, durable, but expensive
• Urbanite: recycled concrete, cheap/free, long-lasting
• Fired bricks: variable cost, reusable options available
• Concrete blocks: usable, but cinder blocks are fragile
• Poured concrete: strong but more labor-intensive and less natural-looking

Building the Walls

1. Get some hay bales
2. Throw cob onto the hay bales
3. Use a stick to poke the cob deeper into the bales for better insulation
4. Add cob between stacked hay bales to help them stick together
5. Wait for the cob to dry before stacking too high to avoid excess weight
6. There are many other ways to create the walls. BE CREATIVE!

The Roof

• Pretty much any roof will work!