Insulation and air sealing for Unincorporated Berkeley County homes: attics, crawl spaces, rim joists and walls, starting with a free assessment of the R-value you actually have. Unincorporated Berkeley County enforces the 2009 IECC (state law), which sets R-30 for a new attic.
This page covers the parts of the county that are not inside a city — where the county, not a municipality, runs building and permits. The Census does not publish population or housing totals for that remainder on its own, so this page does not quote any: the figures you will see elsewhere for “Berkeley County” include every municipality in it as well.
For Berkeley County as a whole, municipalities included, the Census Bureau's 2020–2024 estimates give a median year built of 2002, with 1% of its 100,600 homes built before 1940. The unincorporated remainder has no figures of its own.
No completed job in Unincorporated Berkeley County is logged in our records yet, and this page will say so until one is.
Unincorporated Berkeley County enforces the South Carolina Energy Standard (the 2009 IECC), by state law. The county's residential construction application lists the 2009 International Energy Conservation Code and the 2021 residential code, with no local amendments.
Under that edition the required attic value for new work here is R-30, and walls R-13. For comparison, the Department of Energy recommends R49 for an uninsulated attic in climate zone 3A, where Unincorporated Berkeley County sits, and R38 where there are already a few inches up there.
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).
Nothing Unincorporated Berkeley County publishes settles this. Its permit lists name the work types it cares about, and insulation is not among them in either direction. Berkeley County says an approved permit must be in hand before any type of construction begins, that some buildings are exempt, and that owners should call the permit office about their specific project. It does not say whether adding insulation needs a permit. Its residential permit application includes a 'Repair/Remodel' permit type and asks for the cost of the job. So we ask the department directly before the first day on site, and whatever comes back, pulling it is our job rather than yours.
Berkeley County says it does not issue or require a business license, though many of the towns inside it do. Its residential permit application asks for the contractor's South Carolina LLR license number.
The published number is 843-719-4292. The department page is here.
Permitting is on us, not on you.
Berkeley Electric Cooperative's own territory map shows its service reaching into Unincorporated Berkeley County, and Dominion Energy South Carolina, Santee Cooper and Edisto Electric Cooperative also serve Berkeley 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. Santee Cooper's 2026 program pays $500 toward replacing most of a home's ductwork, but nothing toward insulation. Income-qualified households can apply to Palmetto Community Action Partnership (843-720-5336) for free weatherization instead. The Berkeley County page and the rebate guide carry the full rules.
Every layer of an insulated attic, explained
Elsewhere in Berkeley 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 2 of the 7 publish a permit rule for insulation.
| City | Energy code | Attic R required | Permit to insulate | Building dept. |
|---|---|---|---|---|
| Unincorporated Berkeley County | 2009 IECC (state law) | R-30 | Not published | 843-719-4292 |
| Bonneau | 2009 IECC (state law) | R-30 | Not published | 843-825-3385 |
| Daniel Island | 2009 IECC (state law) | R-30 | Yes | 843-577-5550 |
| Goose Creek | 2009 IECC (state law) | R-30 | Not published | 843-797-6220 ext. 1508 |
| Hanahan | 2009 IECC (state law) | R-30 | Yes | 843-576-5259 |
| Ladson | 2009 IECC (state law) | R-30 | Not published | 843-719-4292 |
| Moncks Corner | 2009 IECC (state law) | R-30 | Not published | 843-719-7914 |
All 10 Berkeley County jurisdictions side by side →
Unincorporated Berkeley County 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.
Not on paper: Unincorporated Berkeley County names neither a permit nor an exemption for insulation, so one call to the department at 843-719-4292 settles it first.
Dominion Energy South Carolina's Check-up Plus pays 90% of attic insulation, air sealing and duct sealing, up to $2,880, until March 31, 2027, for electrically heated homes; the program's contractor does the work. Berkeley Electric members get a 5% on-bill loan instead of a rebate. Santee Cooper pays $500 toward ductwork only. 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: web.archive.org (2, 3, 4, 5, 6, 7, 8, 9, 10, 11) · scstatehouse.gov · berkeleycountysc.gov (2, 3, 4, 5, 6, 7, 8, 9, 10, 11) · dominionenergy.com · berkeleyelectric.coop · santeecooper.com · coastal.coop · energystar.gov. These change; confirm with the building department at 843-719-4292 or the utility named on your electric bill first.
Free assessment, a measured R-value, and photos you keep either way.
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