Dankotuwa terracotta roof tile clamp kilns: paddy husk firing temperature profiles?

Artisanal tile manufacture in the Maha Oya basin at Dankotuwa relies on wood-and-husk clamp kilns holding up to 30,000 pressed terracotta tiles. Unfired green tiles (pressed from alluvial clay and de-aired in pug mills) are stacked in open lattice checkerboard patterns over combustion flue vaults. Firewood logs (split rubber and coconut wood) provide initial heat for 48 hours to drive out hygroscopic moisture. The kiln is then blanketed with a 30cm outer layer of rice paddy husk (Dahayya) and sealed with wet mud. The husk smolders slowly without flame, generating an even 850°C to 950°C soaking heat that vitrifies iron-rich clay into deep terracotta red.