posted 7 years ago
I wouldn't use cob for boat building. If you were looking to do interior walls natural, wattle and daub might be a good idea. Cob is not waterproof, but will soak up moisture and crumble apart. As previously mentioned, cob is also very heavy and not ideal for floating. You can make water resistant clay plasters and waterproof lime plasters called tadelakt, but I would stick to wood for boat building.