Light clay is an infill material created by tossing loose straw or other agricultural fibers in a diluted clay slurry until lightly coated. Builders pack this wet mixture into wall cavities or formwork to create highly insulating, breathable walls. Because it consists mostly of air pockets trapped by the straw, it cannot support structural loads and relies entirely on a timber frame.
Heard on the job
Pack the light clay tightly into the timber frame forms before the slip dries out on us.
Insider tip
Because it holds a lot of moisture when first packed, light clay must be left to dry completely before any render or plaster is applied to prevent mold.
Also heard as
- straw-clay
- slip-straw