Insulation and air sealing for Unincorporated Dorchester County homes: attics, crawl spaces, rim joists and walls, starting with a free assessment of the R-value you actually have. Unincorporated Dorchester 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 “Dorchester County” include every municipality in it as well.
For Dorchester County as a whole, municipalities included, the Census Bureau's 2020–2024 estimates give a median year built of 2000, with 2% of its 67,865 homes built before 1940. The unincorporated remainder has no figures of its own.
We have not logged a completed job in Unincorporated Dorchester County yet. We would rather say so than put a number on this page that is not real.
Unincorporated Dorchester County enforces the South Carolina Energy Standard (the 2009 IECC), by state law. The county lists the 2009 International Energy Conservation Code, and County Code Sections 6-21 and 6-22 adopt the editions the state Building Codes Council has adopted as of January 1 each year.
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).
Unincorporated Dorchester County publishes no answer either way. Insulation and air sealing appear on neither the permit-required list nor the exempt list. Dorchester County Building Services says it issues residential permits for new construction and renovations, and its permit application includes an 'Alteration/Addition/Renovation' permit type, but the county does not publish whether adding insulation alone needs a permit. Its fee schedule lists no value below which a permit is not needed; even permitted work valued at $1,000 or less has a $60 minimum fee ($90 in a flood hazard area). We confirm it with the department before we start and pull whatever is needed. We would rather write that here than guess on your behalf.
The published number is 843-832-0011. 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 Dorchester County, and Dominion Energy South Carolina, Edisto Electric Cooperative and Coastal Electric Cooperative also serve Dorchester 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. Coastal Electric members can borrow up to $10,000 on the bill; Edisto Electric lists no insulation program. Income-qualified households can apply to Palmetto Community Action Partnership (843-720-5336) for free weatherization instead. Every condition attached is on the Dorchester County page and in the rebate guide.
Every layer of an insulated attic, explained
Elsewhere in Dorchester 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 none of the 4 publishes a permit rule for insulation.
| City | Energy code | Attic R required | Permit to insulate | Building dept. |
|---|---|---|---|---|
| Unincorporated Dorchester County | 2009 IECC (state law) | R-30 | Not published | 843-832-0011 |
| Ridgeville | 2009 IECC (state law) | R-30 | Not published | 843-832-0011 |
| St. George | 2009 IECC (state law) | R-30 | Not published | 843-563-3032 |
| Summerville | 2009 IECC (state law) | R-30 | Not published | 843-851-5200 |
All 4 Dorchester County jurisdictions side by side →
Unincorporated Dorchester 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.
Unincorporated Dorchester County publishes no rule either way, so we ask its building department at 843-832-0011 before the job is scheduled.
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. Coastal Electric lends up to $10,000. 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: dorchestercountysc.gov (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13) · scstatehouse.gov · library.municode.com · ridgevillegov.com · dominionenergy.com · berkeleyelectric.coop · santeecooper.com · coastal.coop · energystar.gov. These change; confirm with the building department at 843-832-0011 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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