Coastal & Raised Home Gutters in Charleston, SC

Sources: gallons computed as roof sq ft x inches x 0.623; Galvalume distances from the MBCI marine environments technical bulletin; 5 ft from the DOE Building America Solution Center.

Keep copper runoff off other metals

The Copper Development Association puts it plainly: “Care should be taken to prevent the wash from copper surfaces onto adjacent, exposed less noble metal surfaces.” In practice that means no copper gutter dumping onto an aluminum one, no copper valley draining into a galvanized trough and no mixed metals touching at a hanger. On a historic downtown house or an island home with copper accents, we plan the whole drain path in one metal.

Source: Copper Development Association, Architectural Copper FAQs.

Keep the trough clean, too

Metal choice is half of it. Pine straw and live oak leaves left in a trough stay wet and hold moisture against the metal for weeks, and an overflowing gutter dumps water at the piers no matter what is at the bottom of the downspout. So we start at the roof edge: a gutter cleaning and flush test, repairs for loose hangers and leaking seams, and, under live oaks and pines, BroGuard fine mesh gutter guards so the downspouts below never clog.

Source for distances: U.S. Department of Energy Building America Solution Center, “Gutters and Downspouts”, which also calls for the ground to fall at least 0.5 inch per foot for the first 10 feet.

How we handle it

A Solutionist follows each downspout from the gutter to where it empties, checks the metal and the hangers for salt wear, marks the wet spots under the house you show us and plans a route for each one in writing. Every gutter, downspout and extension is installed by our own Charleston crews, and Gabe Gomez’s local team out of Mount Pleasant stays your contact from the first call to the final water test.

Downspout work holds up best with the right gutter above it: properly sized troughs and a mesh guard on top so pine straw and oak leaves never reach the downspouts. Skip the guard and a downspout can clog in the middle of a summer storm, right when you need it most.

• Water standing under the house or around the piers hours after the rain stops.
• Sand washed out, or channels cut, below a downspout or extension.
• A downspout emptying onto the stairs, the parking pad or toward a flood vent.
• Water sheeting over the front of a gutter below a metal roof in a downpour.
• Long downspout drops down the pilings swaying, pulled loose or missing straps.
• Rust streaks, white powder or pitting on gutters, hangers or screws.
• Green stains on aluminum or painted trim below a copper gutter or flashing.
• Rotted trim or fascia low on the house or the stairs, a sign water has been sitting there.

Flood vents and the space under the house

Many raised homes here sit in a FEMA flood zone, with flood vents in the walls around the space below. In A zones, FEMA’s Technical Bulletin 1 calls for at least two flood openings within a foot of grade so floodwater flows in and out on its own, and limits that space to parking, building access and storage. We keep downspouts and extensions clear of the vents and never box one in. What your home requires is a question for your local floodplain office.

If salt air and standing water have rotted wood along the roofline, fascia board replacement can be done with the gutter work, and if a metal roof is overshooting a small gutter, 6 inch gutters catch more and carry more to each downspout.

Ordinary rain adds up. Charleston International Airport averages about 16 days a year with an inch of rain or more, based on 1991 to 2020 records. Summer storms come harder: NOAA’s Atlas 14 puts the one-hour rain the airport should expect about once a year at 1.70 inches, which sends about 35 gallons a minute off a 2,000 square foot roof.

Then there are the big ones. On October 3, 2015, the airport measured 11.50 inches, its greatest one-day rainfall on record, beating 10.52 inches from September 21, 1998. Counting October 1 to 3, the airport took 14.48 inches, another record. On a 2,000 square foot roof, 11.50 inches is about 14,330 gallons, all of it headed for your downspouts in a single day.

Tides make it harder. The City of Charleston says rain within two hours of high tide drains significantly slower, because its pipes and ditches are already full of seawater. NOAA logged coastal flooding on 39 separate days in our counties from 2016 to 2025.

Sources: NOAA ACIS station data, Charleston airport, 1991 to 2020 (computed); NOAA Atlas 14, Charleston International Airport; NWS Charleston rainfall records; City of Charleston drainage and tides; NOAA NCEI Storm Events Database (computed).

Got a metal roof on top?

Plenty of Lowcountry homes do, from standing seam on island houses to metal over new builds in Summerville. Metal sheds rain off the eave faster than shingles, and in a 1.70 inch hour a gutter that is too small or hung too low gets overshot, so the water lands at the piers anyway. We set the gutter where the water actually leaves the roof, size it for the flow and add downspouts where one drop cannot keep up. On a raised house that drop can run two stories, so it gets strapped to the structure along the way.

Source: NOAA Atlas 14, Charleston International Airport, 1-year 60-minute rainfall, 1.70 inches.