ASHRAE 90.1 is the energy code for commercial buildings. Here are the cavity insulation minimums by climate zone.
Residential buildings (1–3 stories of residential use) fall under IECC. Commercial buildings — including multifamily over 3 stories — follow ASHRAE 90.1, the energy standard adopted by most states and required by federal construction. Understanding which applies determines your minimum insulation R-values.
| Climate Zone | Mass Wall | Metal Frame Wall (ci) | Wood Frame Wall |
|---|---|---|---|
| Zone 1–2 | R-3.8 ci | R-13 + R-3.8 ci | R-13 |
| Zone 3 | R-7.6 ci | R-13 + R-7.6 ci | R-13 + R-3.8 ci |
| Zone 4 | R-11.4 ci | R-13 + R-7.6 ci | R-13 + R-3.8 ci |
| Zone 5 | R-13.3 ci | R-13 + R-11.4 ci | R-13 + R-7.5 ci |
| Zone 6 | R-15.2 ci | R-13 + R-11.4 ci | R-13 + R-7.5 ci |
| Zone 7–8 | R-19 ci | R-13 + R-15.2 ci | R-13 + R-15.2 ci |
ci = continuous insulation (applied over structural members, no thermal bridging). For wood frame walls, the cavity batt component is standard fiberglass — the ci component is typically rigid foam or mineral wool board.
| Climate Zone | Insulation Entirely Above Deck | Attic and Other |
|---|---|---|
| Zone 1–3 | R-20 ci | R-30 |
| Zone 4–8 | R-25 to R-35 ci | R-38 to R-49 |
For wood-frame commercial walls under ASHRAE 90.1, the cavity batt is typically R-13 or R-21 — the same products used in residential construction. The continuous insulation component (rigid foam boards) is a separate spec. We supply the cavity batt portion: R-13, R-15 HD, R-19, R-21 HD, and mineral wool for fire-rated assemblies.
Commercial buildings under IBC have specific fire-rated assembly requirements for party walls, corridor walls, and floor/ceiling assemblies. Non-combustible mineral wool (AFB and SAFB) is typically required in these assemblies — it's ASTM E136 non-combustible and supports UL-listed 1-hr and 2-hr assemblies. See our fire-rated insulation page for full UL assembly details.
Same-day quote, next-day delivery on stocked products. Call or text anytime.
Leave your number and what you need — we text or call you back with a quote the same day.
Or reach us directly: (929) 466-1426 · Text us