What actually governs a roof in this metro, what does not, and which of the things contractors tell homeowners are true. Written to be checkable — every claim below names its source.
South Carolina has one building code for the whole state. State law (S.C. Code 6-9-10) requires every city, town and county to enforce the codes the South Carolina Building Codes Council adopts, and only those; a town that wants a local variation needs the Council's approval (6-9-105). The residential code in force is the 2021 International Residential Code with South Carolina's changes, in effect since January 1, 2023. The Council adopted the 2024 edition on August 26, 2025, and local building departments start enforcing it on January 1, 2027.
The South Carolina changes that touch a roof: houses are designed to the wind speeds on the Council's county maps, which the local building official applies; shingles must carry the wind rating the code sets for that speed; the roof needs a continuous load path down to the foundation; and drip edge on an asphalt shingle roof is required only where the shingle maker requires it. Each city, town and county still sets its own permit rules, fees and inspections, which is why the town pages differ.
South Carolina regulates roofers through two boards at its Department of Labor, Licensing and Regulation. On a house, a roofer is a residential specialty contractor and must be registered with the Residential Builders Commission for any job over $500 (S.C. Code § 40-59-20 and § 40-59-220), and on a homeowner's job over $5,000 the roofer also needs a surety bond (§ 40-59-240). Registration involves no exam. Commercial roofing over $10,000 needs a license from the Contractor's Licensing Board (§ 40-11-30). Both boards keep an online lookup at llr.sc.gov, so you can check a roofer before you sign. Many cities and towns in the Charleston area also require their own business license before they issue a permit.
| Criterion | Figure | What it drives |
|---|---|---|
| Ultimate design wind (Vult) | 133–150 mph | Fastener schedule and the manufacturer wind rating we specify |
| Nominal design wind (Vasd) | 103–116 mph (derived, not published locally) | The allowable-stress figure older specs quote |
| Ground snow load | 5 psf | Roof framing, not the roof covering |
| Frost depth | No single figure | Footings, not roof covering |
| Seismic design category | C–D2 residential / D commercial | Lateral bracing and structural connections — not shingles |
Vasd = Vult x sqrt(0.6): 133 x 0.7746 = 103 mph and 150 x 0.7746 = 116 mph. These are computed conversions, not figures any jurisdiction here publishes. The ultimate figures themselves change across the metro: 150 mph in the City of Charleston's and Folly Beach's design tables, 140 to 150 mph between the lines of the state's Charleston County map, 140 mph and up in Goose Creek, 140 mph in Dorchester County, and a 133 mph minimum for plans in unincorporated Berkeley County.
The code sets minimums; the shingle manufacturer sets the rest. These are the layers, from the frame up.
The Charleston earthquake of August 31, 1886 is the largest historical earthquake in the United States east of the Appalachian Mountains, by the U.S. Geological Survey's account, at about magnitude 7. The state's approved code maps put houses across the three counties in seismic design categories C–D2, and most of the building departments here publish D2 for houses and D for commercial buildings.
On nailing, the code minimum and the shingle maker's instructions are two different things. The code minimum is four nails per strip shingle. The code also points to the maker's installation instructions, and those can ask for more nails than the code minimum, often for the shingle's wind rating; the maker's warranty depends on following them. So the number worth asking any roofer about is the one in the instructions for the shingle being quoted, and whether the quote follows it.
Whether an ice barrier is required is set by each jurisdiction's design table, in its 'ice barrier underlayment required' entry. Of the jurisdictions here that publish one, the City of Charleston's and Folly Beach's say No, and Goose Creek's says Yes.
Hail does fall on this coast. Across the three counties on this site, NOAA's Storm Prediction Center logged 83 reports of hail 1 inch or larger from 2016 through 2025, on 34 days, 2 of them in 2025 alone. Each city and county page counts its own. Those are reports from spotters and the public, logged by NOAA's Storm Prediction Center with a location, not a full count, so anyone quoting you a precise “hail events per year” figure for one street is extrapolating.
What matters for your roof is simpler than a statistic: hail damage is often invisible from the ground and obvious from the roof, insurers generally give you a limited window from the date of loss to file, and a bruised mat can look fine for two years and then fail. That is why the inspection is free and photographed.
Each of these pages goes deeper on one job, with the same sources: roof replacement, roof repair, storm damage, roof inspection, roof ventilation, metal roofing, gutters, roof shingles, flat roofing, hurricane roof protection. Every city page adds the permit rule and code edition for that city, plus its own Census housing figures and hail reports.
Free inspection, photographed, and the report is yours either way.
Researched 2026-10-24. Sources: llr.sc.gov · llr.sc.gov · llr.sc.gov · llr.sc.gov · llr.sc.gov · llr.sc.gov · llr.sc.gov · llr.sc.gov · www.scstatehouse.gov · www.scstatehouse.gov · www.scstatehouse.gov · www.charleston-sc.gov · cityoffollybeach.com · www.goosecreeksc.gov · berkeleycountysc.gov · www.dorchestercountysc.gov · llr.sc.gov · llr.sc.gov · llr.sc.gov · llr.sc.gov · sullivansisland.sc.gov · www.summervillesc.gov · www.usgs.gov · earthquake.usgs.gov. Rules and staff change; check with the jurisdiction.