Insulation and air sealing for Wadmalaw Island homes: attics, crawl spaces, rim joists and walls, starting with a free assessment of the R-value you actually have. Wadmalaw Island enforces the 2009 IECC (state law), which sets R-30 for a new attic.
We cover ZIP code 29487.
Our job history shows nothing in Wadmalaw Island so far. Plenty of sites will show you a number here anyway.
That includes Rockville. Housing age and construction shift across Wadmalaw Island, sometimes by decades within a few streets, which is why we look in the attic before quoting rather than after.
Wadmalaw Island is a rural Sea Island southwest of Johns Island, about 10 miles long and 6 miles wide, with its only road link a bridge over Church Creek. It is bounded by Bohicket Creek, the North Edisto River and the Wadmalaw River, and is home to the Charleston Tea Garden and the old summer village of Rockville at its southern tip.
Wadmalaw Island enforces the South Carolina Energy Standard (the 2009 IECC), by state law. Outside the Town of Rockville the island is unincorporated, so Charleston County's code list applies, 2009 energy standard included.
For new work, the attic number under that edition is R-30, with walls at R-13. Set that against the Department of Energy, which recommends R49 for an uninsulated attic in this climate zone and R38 for one that already has a few inches.
Table 402.1.1 of the 2009 IECC, climate zone 3, which South Carolina's Energy Standard Act adopts for the whole state (section 6-10-30 of the South Carolina Code).
Wadmalaw Island requires a permit for this work. Outside the Town of Rockville, Wadmalaw Island follows Charleston County's building code, which names insulation as work that needs its own permit; the county's sub-trade form lists fiberglass and spray foam insulation. Per the county FAQ, only a job under $1,000 that needs no inspection, done by the homeowner or by a one-trade specialty contractor, can go without a permit. We pull it as part of the job.
The published number is 843-202-6930. The department page is here.
Permitting is on us, not on you.
Berkeley Electric Cooperative's own territory map shows its service reaching into Wadmalaw Island, and Dominion Energy South Carolina also serves Charleston County, so the name on the electric bill decides which program applies. Dominion Energy South Carolina's Check-up Plus is the big one: 90% of attic insulation, air sealing and duct sealing paid, up to $2,880, until March 31, 2027, for electrically heated homes that have had the free check-up, with the work done by Dominion's approved contractor.
Berkeley Electric lends rather than rebates: its HomeAdvantage program lends up to $20,000 at 5%, with an energy audit first and the payments added to the electric bill. Income-qualified households can apply to Palmetto Community Action Partnership (843-720-5336) for free weatherization instead. The Charleston County page and the rebate guide carry the full rules.
Every layer of an insulated attic, explained
Wadmalaw Island borders Johns Island, Rockville, Seabrook Island, Church Creek, Bohicket Creek and North Edisto River. These are the ones we also cover, each with its own energy code and permit rule:
Elsewhere in Charleston County we also cover:
South Carolina sets the residential energy code statewide, so the attic figure is R-30 wherever it is published here; what changes is the permit desk, and 7 of the 7 publish a permit rule for insulation.
| City | Energy code | Attic R required | Permit to insulate | Building dept. |
|---|---|---|---|---|
| Wadmalaw Island | 2009 IECC (state law) | R-30 | Yes | 843-202-6930 |
| Johns Island | 2009 IECC (state law) | R-30 | Yes | 843-577-5550 |
| Rockville | 2009 IECC (state law) | R-30 | Yes | 843-202-6930 |
| Seabrook Island | 2009 IECC (state law) | R-30 | Yes | 843-202-6930 |
| Adams Run | 2009 IECC (state law) | R-30 | Yes | 843-202-6930 |
| Awendaw | 2009 IECC (state law) | R-30 | Yes | 843-202-6930 |
| Charleston | 2009 IECC (state law) | R-30 | Yes | 843-577-5550 |
All 22 Charleston County jurisdictions side by side →
Wadmalaw Island enforces the 2009 IECC (state law), which sets R-30 for an attic in new work. Whether it reaches a retrofit of an existing house is not published.
Yes. Wadmalaw Island requires a permit for this work, and we pull it as part of the job.
If Dominion Energy South Carolina is your electric utility and the house has electric heat, Check-up Plus pays 90% of attic insulation, air sealing and duct sealing, up to $2,880, through March 31, 2027, through its own contractor. Berkeley Electric members get a 5% on-bill loan instead of a rebate. The federal 25C credit ended for work placed in service after December 31, 2025.
Code and permit facts checked October 24, 2026, rebates October 24, 2026; housing: Census ACS 2020–2024. Sources: charlestoncounty.gov (2, 3, 4, 5, 6, 7, 8, 9, 10, 11) · scstatehouse.gov · townofrockville.com (2) · llr.sc.gov · en.wikipedia.org (2) · nationalregister.sc.gov · www2.census.gov · dominionenergy.com · berkeleyelectric.coop · santeecooper.com · coastal.coop · energystar.gov. These change; confirm with the building department at 843-202-6930 or the utility named on your electric bill first.
Free assessment, a measured R-value, and photos you keep either way.
Book my free assessment →