Which insulation do mice not eat? - briefly
Fiberglass and mineral‑wool insulation, especially when treated with bittering agents, are not consumed by mice.
Which insulation do mice not eat? - in detail
Rodent‑resistant insulation options fall into three principal categories.
- Mineral wool (rock wool) – dense, non‑organic fibers resist chewing; mice cannot derive nutrition from the material and the high melting point discourages gnawing.
- Fiberglass batts – glass fibers lack digestible content; the brittle structure and embedded binders make the material unappealing to rodents.
- Closed‑cell foam board (polyisocyanurate, extruded polystyrene) with foil or metal‑reinforced skins – rigid, non‑cellular composition provides no edible substrate; the smooth surface and added metal layer further deter gnawing.
Supplementary measures improve effectiveness. Sealing gaps around joists and ducts eliminates entry points, while metal mesh or wire mesh placed over insulation adds a physical barrier. Installing a vapor‑barrier foil on the exterior of foam board prevents moisture accumulation, which can otherwise attract rodents.
Materials such as cellulose, cotton batting, or loose‑fill fiberglass are unsuitable because they contain organic fibers that mice can chew and ingest. Selecting dense, inorganic, or encapsulated insulation, combined with proper sealing, offers the most reliable protection against rodent damage.