Building Codes
Georgia Insulation Requirements: A Climate Zone Guide
Georgia spans three IECC climate zones — from hot-humid south Georgia to the mixed-humid mountains near the Tennessee and North Carolina borders. Requirements shift meaningfully depending on where in the state a job sits. Here's the breakdown by zone.
Georgia's climate zones
| Zone | Cities / Region | Description |
|---|
| 2A | Valdosta, Thomasville, far south Georgia | Hot-humid |
| 3A | Atlanta, Savannah, Macon, Augusta, Columbus — most of the state | Mixed-humid |
| 4A | Blue Ridge, Dahlonega, far north Georgia mountains | Mixed-humid (cooler) |
Zone 2A requirements (far south Georgia)
| Assembly | Typical IECC Minimum | Common Spec |
|---|
| Above-grade walls (2×4) | R-13 | R-13 kraft-faced |
| Above-grade walls (2×6) | R-19 | R-19 or R-21 |
| Attic floor | R-30 | R-30 to R-38 |
| Floor over unconditioned | R-13 | R-13 or R-19 |
Zone 3A requirements (Atlanta, Savannah, Macon, Augusta)
| Assembly | Typical IECC Minimum | Common Spec |
|---|
| Above-grade walls (2×4) | R-13 + R-3.75 ci, or R-15 | R-15 HD (most common in newer builds) |
| Above-grade walls (2×6) | R-19 to R-21 | R-21 HD |
| Attic floor | R-38 | R-38 to R-49 |
| Floor over unconditioned | R-19 | R-19 or R-30 |
Zone 4A requirements (North Georgia mountains)
| Assembly | Typical IECC Minimum | Common Spec |
|---|
| Above-grade walls (2×4) | R-13 + R-3.75 ci, or R-20 | R-20 or R-13+5ci |
| Above-grade walls (2×6) | R-20+R-3.75ci or R-21 int + R-2.5ci | R-21 HD + rigid foam |
| Attic floor | R-49 | R-49 blown-in |
| Basement wall | R-10 continuous or R-13 cavity | R-13 cavity common |
Georgia adopts code on a delay — always confirm locally
Georgia's statewide energy code adoption has historically lagged the national IECC cycle, and some jurisdictions layer their own amendments on top. The values above reflect typical, widely-used specs for each zone, but the exact minimum enforced on a given permit depends on which code edition your local building department has adopted and when. Always confirm the current requirement with the county or city building department before finalizing a spec — this is standard practice regardless of state, but matters more in Georgia given adoption timing varies more than in some neighboring states.
What we hear most from Georgia contractors
- Metro Atlanta new construction is almost entirely zone 3A specs — R-15 or R-13+3.75ci walls and R-38 attics are the norm on current permits.
- Coastal Georgia (Savannah, Brunswick) runs hot-humid similar to zone 2A in practice, even though it's technically mapped 3A — mineral wool is a common upgrade near the coast for moisture resistance.
- North Georgia mountain builds see the highest R-value requirements in the state and are the one area where basement wall insulation is commonly required.
Ready to order?
Same-day quotes, next-day delivery on stocked product. Pay at delivery.