insulation
Open-cell spray foam
Lower-density spray foam with R-3.5-3.8 per inch. Less expensive than closed-cell; vapor-permeable so wall assembly can dry.
Cost tier
MID
Cost / sqft
$1.5–$4
Install
specialty
Durability
high
Maintenance
low
Moisture
good
Cost notes
Typical pick for unvented attics in mixed climates. Vapor-permeable allows wall to dry inward.
Aesthetic
- Finish: concealed
- Color range: white to off-white
- 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: spray-foam, open-cell, air-barrier