Why Upstate SC homes get mold
Humidity, crawlspaces, storms and HVAC: the four reasons mold shows up in Greenville and Spartanburg homes, and what to do about each.
Mold needs three things: spores, something to feed on, and moisture. Spores are everywhere, inside and out, and drywall, wood and dust are all food. So the only one you can really control is moisture. In the Upstate, moisture comes from four main places.
1. Long, humid summers
From late spring into early fall, outdoor humidity here is high most days. Any time that air reaches a cool surface, like a duct, a window, or the underside of a floor above a crawlspace, it can condense. Indoors, keeping relative humidity below about 60 percent, and ideally between 30 and 50 percent, makes mold growth much less likely.
2. Vented crawlspaces
A large share of Upstate homes, especially older ones in Greenville, Spartanburg and Anderson, sit on vented crawlspaces. Those vents were meant to let moisture out, but in our climate they often let humid summer air in. It hits the cooler soil and framing, and the wood under your floor stays damp. Torn or missing vapor barriers make it worse.
What to watch for: musty smells in rooms over the crawlspace, cupping hardwood floors, and sagging or wet insulation below.
3. Storms and roof leaks
Heavy summer thunderstorms and the occasional tropical system bring a lot of rain at once. Roof valleys, flashing around chimneys and skylights, and gutters that overflow against the foundation are the usual entry points. A leak that's repaired quickly rarely causes mold. A slow leak inside a wall can grow for months before anyone notices.
4. HVAC that doesn't dehumidify
Air conditioners remove moisture as they cool, but only when they run long enough. A system that's oversized for the house cools quickly and shuts off before it pulls out much water. Clogged condensate lines, dirty coils and leaky ducts in hot attics add to the problem. Spotting on supply vents and a musty smell when the AC kicks on are common signs.
What to do
- Run bath fans during and after showers, and make sure they vent outside, not into the attic.
- Fix leaks quickly and dry wet materials within 24 to 48 hours.
- Check your crawlspace vapor barrier and consider encapsulation or a dehumidifier if it stays damp.
- Have your HVAC serviced, including the condensate drain.
- If you smell mustiness or see recurring growth, find the source before you clean, or it will come back.
If you're not sure where moisture is coming from, a mold inspection with moisture mapping and air testing will tell you.
Find out what's in your air.
Tell us what's going on and we'll recommend the right test. Most appointments are scheduled within a few days, and lab results come back in 2 to 3 business days.