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Residential · Gwinnett County, GA
NJ Spray Foam LLC installs residential spray foam across Gwinnett County, GA, from Lawrenceville and Buford to Snellville and Duluth. Gwinnett has about 153,000 owner-occupied single-family homes (Census), most built in the 1990s, and the whole county follows Georgia's climate zone 3A code.
Residential Spray Foam in Gwinnett County
Southwest Gwinnett skews to late-1980s homes, the I-85 corridor to the mid-1990s and the north and east of the county to the 2000s and 2010s. Older homes need air sealing most; newer ones need their attic ducts brought inside.
Remodels open walls and ceilings, the best moment to spray foam. For new homes and additions in unincorporated Gwinnett, the county requires an energy code affidavit listing insulation R-values, and we give your builder the product data.
Homes near Lake Lanier in Buford and Sugar Hill deal with summer humidity. Sealing the roof deck and rim joists keeps damp air away from ducts and living space.
Open-cell and closed-cell spray foam for new and existing homes, applied to roof decks, exterior walls, rim joists and floors so the house is insulated and air-sealed in one step.
Gwinnett County Planning & Development permits unincorporated areas and requires the energy code affidavit for new homes and additions. City addresses follow the city's process; we confirm it for yours.
| Location / item | Limit |
|---|---|
| IECC climate zone | 3A (warm, humid) |
| Attic floor (ceiling) insulation | R-38, or R-30 at full depth over the top plates |
| Spray foam at the roof deck (unvented attic) | R-20 minimum on the trade-off path |
| Wood-frame exterior walls | R-13 |
| Unvented crawl space walls | R-13 cavity or R-5 continuous |
| Air leakage test on new homes | Under 5 ACH50, by a certified verifier |
| New-home permits (unincorporated) | Energy code compliance affidavit |
| Open-cell | Closed-cell | |
|---|---|---|
| R-value per inch | About R-3.5 to R-3.8 | About R-6 to R-7 |
| Air sealing | Yes, seals gaps as it expands | Yes, and adds rigidity |
| Moisture | Vapor-open; assemblies can dry | Acts as a vapor retarder |
| Typical use in homes | Roof decks, interior side of walls | Rim joists, crawl spaces, below grade |
We look at the attic, walls and crawl space, measure the areas and note ducts, wiring and moisture.
Open-cell or closed-cell, thickness and target R-values set against Georgia's energy code for your climate zone.
We cover floors, windows and fixtures and set up ventilation for the spray area.
Foam is applied in passes to the specified depth, then trimmed flush where walls will be closed.
We remove waste and overspray and walk the finished areas with you.
Yes, every city and the unincorporated areas, from Buford and Sugar Hill to Lawrenceville, Snellville, Duluth and Norcross.
The whole county is climate zone 3A: R-13 walls and R-38 ceilings (R-30 at full depth over the plates), or R-20 of spray foam at the roof deck on Georgia's trade-off path.
Yes. We spray after rough-in and before drywall and provide the R-values your builder needs for the Gwinnett energy code affidavit.
NJ Spray Foam LLC installs residential spray foam across Gwinnett County and nearby areas. Send your address and photos to get started.
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