Homeowner Guide

Why Is My Roof Leaking?

A water stain on the ceiling or a drip during a rainstorm is one of the most common reasons South Carolina homeowners call us. The leak itself is rarely the hard part to fix — finding where the water is actually getting in is. Here's what usually causes it and how to think about what you're seeing.

The Most Common Sources

Water almost never enters a roof at the spot where the stain shows up inside — it travels along rafters or decking before it drips. These are the sources we trace leaks back to most often, in roughly the order we see them:

• Flashing failures — the metal seals around chimneys, skylights, and vent pipes are the single most common leak point; sealant cracks with age and lets water track down into the roof deck
• Worn or lifted shingles — shingles that have curled, cracked, or lost their seal from age and heat exposure no longer shed water the way they should
• Valley failures — the seams where two roof planes meet channel a large volume of water; if the valley material has worn through or was installed poorly, this is a frequent leak source
• Aging underlayment — the water-resistant barrier beneath the shingles degrades over decades; once it fails, even intact-looking shingles above it won't stop water from reaching the deck

Leak vs. Something Cosmetic

Not everything that looks concerning on a roof is an active leak. Algae or moss staining on shingles — common across South Carolina given the humidity from the Upstate down through the Midlands and Lowcountry — is a cosmetic issue, not a water intrusion problem, unless growth has built up thick enough to hold moisture against the shingle surface. Granule loss in gutters after a hard rain is normal aging, not necessarily a leak by itself. The real distinction is whether water is actually reaching the interior of the house: a ceiling stain, a musty smell in the attic, or visible daylight through the roof deck are signs of genuine intrusion worth an inspection. A shingle that just looks weathered from sun exposure isn't automatically a leak in progress.