Roof Replacement in Charleston

When a roof here is ready to go

One leak is a repair. Replacing is the answer when the wear is spread across most slopes, or when the next storm season is likely to finish what the last one started. What we look for up close:

• Age. A shingle roof past the 20-year mark in HUD's guide has spent its expected life, even if it still sheds water.
• Tabs that have let go. Creased, torn or missing shingles on several slopes mean the adhesive strips have stopped holding.
• Granule loss. Bald patches leave the asphalt open to the sun.
• A soft deck. Sheathing that flexes underfoot cannot hold a nail to the depth the code asks. The City of Charleston's design table rates the risk of termite damage here as very heavy, one more reason the deck gets walked before anyone writes a price.
• Layers. A house that was roofed over once has used up its one recover.

If what we find is a repair, we tell you that and point you to roof repair.

Tear-off or recover: what the code allows

Section R908.3 of the 2021 residential code defines a roof replacement as removing every layer of roofing down to the deck, and South Carolina's lists of changes to the code leave that section alone. The one thing allowed to stay is a bonded ice-barrier membrane, and only if fresh membrane goes over it.

Putting new roofing over old, which the code calls a recover, is barred in three cases (R908.3.1.1):

• the old roof is wet through, or so far gone it cannot act as a sound base;
• it is slate, or clay, concrete or asbestos-cement tile;
• two or more coverings of any kind are already stacked on the deck.

Even a legal recover hides the deck, and the deck and its nailing are what hold a roof down in a hurricane. We take every replacement down to the wood. Rusted or damaged flashings and vents come off too; R908.5 bars reusing them.

Some older houses have board decks laid with gaps, a holdover from wood shingles. Asphalt shingles must be fastened to a solidly sheathed deck (R905.2.1), and Section R803.1 does not allow spaced lumber sheathing in Seismic Design Category D2, the category most building departments here publish for houses. Expect new sheathing over boards like that, as its own line on the quote.

The layers of a new roof, from the frame up

Eight parts make up the roof we put back, numbered in the drawing. Each one, and the line it deserves on a written quote:

1. Rafters or trusses. Left alone on an ordinary job. The state's code changes call for a continuous load path from roof to foundation, so a cracked rafter or missing strap is structural work, priced and permitted on its own.
2. Deck. Plywood or OSB, walked panel by panel, soft sections cut out.
3. Drip edge. South Carolina requires it on asphalt shingle roofs only where the shingle maker does. We put it on regardless.
4. Ice-and-water membrane. Self-adhering, at the eaves and in the valleys.
5. Underlayment. Everywhere else on the deck, by one of the wind-zone methods below.
6. Starter strip. A glued course under the first row at the eave.
7. Shingles. Architectural, in the wind class your address calls for, six nails each (the classes are on roof shingles).
8. Ridge vent. The attic's outlet along the peak, sized against intake vents low on the roof; roof ventilation has the arithmetic.

Underlayment in a wind zone: the county form and the 6-inch rule

Building departments here publish ultimate design wind speeds from 133 to 150 mph, depending on location. Where the code's map says wind design is required, the underlayment rules tighten. Charleston County has the contractor sign a Roof Underlayment Form listing three accepted methods under shingles:

1. Two layers. A 19-inch strip along the eave, then 36-inch sheets each lapped 19 inches over the one below, with 4-inch end laps staggered 6 feet apart.
2. A full self-adhered membrane labeled to ASTM D1970, installed to both the membrane maker's and the shingle maker's instructions.
3. 4-inch strips of that membrane over every deck joint, with an approved underlayment over the whole roof on top.

Fastening matters as much as the sheet. In wind-design areas, Table R905.1.1(3) calls for cap nails with 1-inch caps in a grid 12 inches apart between side laps and 6 inches apart along them. In Mount Pleasant, a 2021 appeal to the Construction Board of Adjustments turned on underlayment nailed at 12-inch spacing; the town's building official has stated that the 6-inch spacing is not discretionary, and that roof was replaced.

Permits filed from January 1, 2027 fall under the state's 2024 code, whose South Carolina changes rewrite that asphalt shingle application rule for wind-design areas to match the ordinary one. The permit date decides which rule your roof follows.

Permits: one code, many permit offices

Every jurisdiction enforces the same code, but each runs its own permit desk. A few examples, from each office's published rules:

The island towns add inspections mid-job. On Kiawah Island the inspector checks the new sheathing once it is nailed and before anything covers it, and Isle of Palms and Sullivan's Island both list sheathing and strapping inspections. The permit is ours to pull; each town's own rule sits on its page under roofing by city.

Historic boards and flood zones

In a historic district the building permit is only half of it:

• City of Charleston: the Board of Architectural Review looks at outside work that shows from a street in the Old and Historic District, and at any outside change at all to a Landmark Overlay property. Preservation staff sign off many in-kind roof swaps at the Permit Center counter.
• Mount Pleasant: inside the Old Village, the roofing permit waits on the town's Historic District Preservation Commission.
• Sullivan's Island: altering a historic house takes a Certificate of Appropriateness from the Design Review Board, a step apart from the permit.
• Summerville, McClellanville and Rockville run their own boards; in Summerville's downtown district, staff can issue the minor certificate a change of roof material needs.

Accepted materials: see metal roofing and roof shingles.

Flood zones add a money test. In the City of Charleston's AE and VE zones, roofing counts toward what flood rules call substantial improvement: once a year's work reaches half of what the building is worth on the market, the whole house has to meet today's flood standards. Charleston County adds up five years of permits for the same test, and Sullivan's Island's form counts re-shingling. On a raised coastal house, ask before you sign.

What drives the price

No price range here: no public figure for this region could be checked when this page was written. What moves the number:

• Size, shape and height. More squares cost more; steep slopes, raised houses and every valley, dormer and chimney add time and flashing.
• What comes off. One layer or two, and how much deck turns out to be rotten.
• The wind rules. Shingle class, underlayment method and nailing for your address.
• Material. Architectural shingles, standing-seam metal, or a membrane for a low-slope section, and whatever a historic board will accept.

On the paperwork side, state law makes a residential roofer hold a registration from the Residential Builders Commission once a job tops $500, and a homeowner's job above $5,000 also needs a surety bond. The state's lookup at llr.sc.gov shows who holds one. If insurance is paying, the contract must carry a cancellation notice under S.C. Code 40-59-25; storm damage explains it.

How a replacement runs

1. Measure and inspect. Measured from aerial imagery first, then every slope, valley and penetration photographed. The photos stay with you, hired or not.
2. Scope. One written, line-item scope naming each product by brand, plus the shingle wind class and the underlayment method.
3. Approvals. Historic or association sign-off first where it applies, then the permit, which is on us.
4. Tear-off. Beds and shrubs tarped, the old roof stripped to the wood.
5. Deck. Soft wood replaced and the deck re-nailed where needed; on the islands, the sheathing inspection happens here.
6. Install. Drip edge, membrane at eaves and valleys, underlayment by the method on the scope, starter, shingles, flashing and ridge vent.
7. Close-out. Daily cleanup and a magnet sweep of the lawn and drive on the last day. One crew from first day to last. You get the finished photos, and the shingle maker's warranty is registered.

Common questions about roof replacement in Charleston

Where we work

Roof replacement across greater Charleston, from the sea islands and beach towns to Summerville, Goose Creek and Moncks Corner. Each city has its own page with the permit rule and code edition that apply there: