Chapter 07 · Materials & footprintsCircular Economy & Materials
Cob
Definition
Cob is a building material of subsoil (clay and sand), water and straw, sometimes with lime, mixed and laid by hand in courses without formwork or firing. It is fireproof, has high thermal mass, and is associated with the natural-building revival and historic vernacular construction in regions such as southwest England.
References
Supports definition and framing.
Overview
What it means
It is one of the lowest-embodied-energy wall systems available, using site-won or local soil instead of manufactured masonry.
How it is used
Built in layers and sculpted while wet; requires protective detailing — a good 'hat and boots' (roof overhang and raised plinth) — to manage moisture.
Why it matters
It offers a low-carbon, non-toxic construction option relevant to sustainable and self-build housing.