Gutter Sizes in Charleston & the Lowcountry

For most homes in North Charleston, Hanahan and Ladson, 6 inch does the job, and it is the size we install on the two-story homes in Summerville, Goose Creek and Mount Pleasant too, with added downspouts where an upper roof empties onto a lower one. Very large, steep or metal roof planes can call for 7 inch. A Solutionist measures before recommending either.

Watch them in a hard rain. A clog overflows at one spot, right where the debris sits. An undersized gutter spills evenly along the run even when it is clean, or water shoots past the front edge. Lower gutters catching an upper roof are the usual suspects.

Roof area, pitch, the shape of the roofline and the local rain pattern. A large, steep roof sends more water, faster, than a small, shallow one. Mixing sizes on one house is often the most cost-effective answer when only part of the roof needs extra capacity.

A run under 40 feet can usually work with one downspout; over 40 feet, plan on two. If a long run cannot take a second downspout, that is a reason to step up to 6 inch. Adding downspouts in the right spots often fixes overflow without changing the gutter at all.

Charleston gets about 52.5 inches of rain a year, and close to half of it falls June through September, much of it in short afternoon thunderstorms. Gutters have to be sized for those downpours, not the average day. Pine straw and oak debris in the trough cut capacity further, so size and cleaning go together.

Low-slope roofs on ranch homes and apartment buildings shed water more slowly, but often from a large area to a single edge. That concentration is what we size for. Some need 6 inch, and big apartment or commercial roofs may call for 7 inch with oversized downspouts.