insulation
Rigid polyiso foam
Polyisocyanurate foam boards with foil facers. Highest R-value of any rigid foam (R-6.5/inch nominal at room temp).
Cost tier
MID
Cost / sqft
$1–$2.5
Install
trade
Durability
high
Maintenance
low
Moisture
good
Cost notes
Cold-temperature derating means XPS often outperforms polyiso in zone 6+ winters despite lower nominal R.
Aesthetic
- Finish: concealed
- Color range: foil-faced
- Visual weight: light
Climate suitability
✓ Hot-humid
✓ Hot-dry
✓ Mixed-humid
✓ Mixed-dry
✓ Cold
✓ Arctic
Source
Architectural Graphic Standards — Architectural Graphic Standards (Ramsey/Sleeper) — Materials chapter
Tags: polyiso, rigid-foam, high-R