Cob oven and papercrete

August 29, 2005

The cob oven base (left), and sand form for the oven dome (right)

Paper pulp being squeezed of excess water (left), mixing papercrete (right)

UHC worked on two projects this weekend at 1309 S. Kedzie: an oven and papercrete experiments.

The cob oven started as an urbanite (chunks of concrete, stone, and cement) base with a gravel and rubble infill. Within a cement leveling ring was placed a bed of fine sand on which were laid firebrick. A mound of coarse sand was built over this as the formwork for a cob (mix of clay, straw,and sand) dome with varying mixes of straw. Once the dome dries, the sand will be dug out to create a chamber for baking delicious breads, pizzas, and cookies.

Papercrete is a mix of Portland cement, sand, paper pulp, and water. The paper takes the place (and the exceesive weight) of the aggregate in traditional concrete. Test bricks with different mixes were poured into soymilk containers (donated by northside coffeeshops Intelligentsia and Cafe Latakia) and left to dry. A small wall cavity inside the carriage house was filled to test how this hybrid material will stand up on its own, the insulative properties, and just what it might look like on a vertical surface when it dries.

Thanks for the new folks who came out to join us - please keep coming!