Charleston Metal Roofing Co.: Standing Seam, Aluminum & Copper Metal Roofing in Charleston, SC

Standing seam panels lock together along raised seams with hidden clips beneath them, so no screw goes through the face of the roof. There are two common kinds. Snap-lock panels press together by hand and suit slopes of 3:12 and steeper. Mechanically seamed panels are folded shut on the roof with a seaming tool, single or double lock, and carry the best uplift values of the two, which counts in a city that designs for hurricane winds. Standing seam can go on slopes as low as 1/4 inch per foot.

Steel panels need at least an AZ50 Galvalume or G90 galvanized coating under the paint. That coating is what an industry field study looked at when it projected more than 60 years of service from unpainted Galvalume standing seam.

See Standing Seam Metal Roof in Charleston, SC.

Aluminum doesn't rust, which is why it shows up on houses facing the harbor, the marsh and the creeks. Steel panel warranties tend to stop at the water's edge: one manufacturer's 25-year Galvalume warranty needs the house 2,800 feet from surf, 1,200 feet from a large bay and 600 feet from a marsh or canal. A lot of Charleston homes sit inside those lines.

Aluminum panels must be at least 0.024 inch thick under the residential code. They usually run in the same standing seam profiles as steel and cost more: one cost guide prices installed aluminum at $700 to $1,700 per 100-square-foot "square".

See Aluminum Roofing in Charleston, SC.

Copper goes on whole roofs, but in Charleston it's more often on the parts people see: dormers, bay windows, cupolas, porch hoods and half-round gutters. The code minimum is 16-ounce copper, or 12-ounce for high-yield copper. Fasteners have to be copper, brass, bronze or 300-series stainless; a plain steel screw in copper corrodes fast.

Copper is also the material the Board of Architectural Review allows as a substitute for terne on many historic buildings, and it costs the most: $1,300 to $3,000 per square installed in one cost guide.

See Copper Roofing in Charleston, SC.

5V crimp is the roof on a lot of older Lowcountry cottages, farmhouses and beach houses: flat panels with five evenly spaced V-shaped ribs, lapped at the edges and screwed through the face. It's simpler and cheaper than standing seam, at $5 to $12 a square foot in one national cost guide against $9 to $16 for standing seam.

Because the side laps are screwed rather than seamed, slope matters. The code wants 3:12 or steeper for laps without sealant, and the screws and their washers need attention over the years.

See 5V Crimp Metal Roofing in Charleston, SC.

Charleston's side piazzas and front porches often have roofs too flat for shingles. Metal handles low slopes well: standing seam is allowed down to 1/4:12, where lapped panels and shingles aren't. The details that keep a porch roof dry are the flashing where it meets the house wall, the transition to the main roof, and gutters sized for summer downpours.

A porch roof is a smaller job and often the first piece of a house to get metal.

See Metal Porch Roof in Charleston, SC.

Many older Charleston houses have terne roofs: steel or iron sheets coated in a lead-tin alloy, joined with flat-locked or standing seams, and kept alive with paint. A sound terne roof can usually be repaired, re-soldered at failed seams and repainted rather than replaced.

Inside the historic districts that's also the rule. The Board of Architectural Review's roofing policy is to repair before replacing, and to replace in kind when a roof is beyond repair. Where terne isn't available, staff can approve aluminum or coated copper in its place.

See Historic Metal Roof Restoration in Charleston, SC.

Metal shingles and stone-coated steel look like asphalt shingles, shakes or tile from the street, which suits a house where standing seam would look out of place or a neighborhood with design rules. Stone-coated panels carry a layer of granules bonded to the steel.

Under the code, metal shingles need a passing wind test (ASTM D3161, FM 4474, UL 580 or UL 1897). Some products also hold a UL 2218 Class 4 impact rating, meaning the covering survived a 2-inch steel ball dropped from 20 feet. Ask for both test results by product name.

See Metal Shingles in Charleston, SC and Stone Coated Steel Roofing in Charleston, SC.

R-panel, corrugated and other ribbed panels are screwed straight through the face into purlins or decking. They're the budget option for garages, barns, workshops, carports, dock houses and boathouses, and for homes where looks matter less than price.

Near salt water, the screws decide how long these roofs last. In the field study mentioned above, 300-series stainless fasteners held up while 400-series ones needed replacing well before the panels did. Ask what the screws are made of, not only the panels.

See Corrugated Metal Roofing in Charleston, SC and Metal Shed and Barn Roofs in Charleston, SC.

Most metal roofs in Charleston replace asphalt shingles. The usual sequence is tear-off, decking repairs, synthetic underlayment, edge metal, panels, flashing and ridge. The code doesn't allow a new covering over a roof that already has two or more layers or is wet or deteriorated. Stripping it also lets the crew find soft decking before the panels hide it.

In the City of Charleston a re-roof needs a permit, and the application for a metal roof has to include the manufacturer's specifications. The contractor files those.

See Metal Roof Replacement in Charleston, SC and Metal Roof Over Shingles in Charleston, SC.

Metal roofs leak in predictable places: screws that have backed out as panels expand and contract in the heat, rubber washers that have cracked, side laps and end laps, flashing at walls, chimneys and vents, and ridge caps lifted by wind. A repair visit finds which one it is. Fixes range from re-screwing with larger gasketed fasteners to resealing laps, re-flashing a chimney or replacing a damaged panel.

Tell us where the water shows up inside and after what kind of weather. Wind-driven rain from the side and slow steady rain point to different places.

See Metal Roof Repair in Charleston, SC.

An older metal roof with sound panels but tired paint or surface rust can often be cleaned, primed and coated instead of replaced. Coating systems seal the seams and fasteners with reinforced fabric first, then cover the whole roof. On a terne roof, repainting on a regular cycle is the maintenance itself.

Factory finishes are a separate matter. Kynar 500 finishes must contain at least 70% PVDF resin; ask which finish a new panel carries before you compare prices.

See Metal Roof Coating and Painting in Charleston, SC.