The Amish insulate homes with what grows in their fields.
Straw Bales
R-value of a straw bale wall (45 cm) is about R-30, comparable to 15 cm mineral wool. Plastered with clay on both sides — fire and moisture protection.
Sawdust with Lime
Mix poured into wall cavities. Lime protects against insects and mold, sawdust insulates. 10 parts sawdust to 1 part lime.
Sheep's Wool
Low-grade wool as insulation. Absorbs up to 30% its weight in water without losing insulation value. Treated with borax against moths.
Clay-Straw Mix
Clay mixed with chopped straw, packed into formwork between posts. Dries into a monolithic wall — slow to heat, slow to cool.
Important
All natural insulation needs moisture protection. Without plaster or cladding, they absorb water. The Amish always cover insulation on both sides.