Mold in Sioux Falls homes
Mold in Sioux Falls homes follows the seasons. Summer humidity condenses in cool basements, and winter brings condensation on cold surfaces and frost in attics. Both come back to moisture.
Summer humidity
NOAA's engineering weather data for Sioux Falls counts about 232 hours a year with the wet-bulb temperature above 73°F and about 892 hours above 67°F. Humid summer air reaching a cool basement condenses on concrete walls, floors and cold-water pipes. Musty odors, mold on stored boxes and mildew on the back of finished walls are typical. A dehumidifier running through the summer and drained to a floor drain usually helps.
Winter condensation
NOAA gives a 99% winter design temperature of −11°F. When outdoor air is that cold, indoor surfaces near the outside get cold too: window glass and frames, closet corners on exterior walls, and the rim joist in the basement. Warm, moist indoor air condenses there, and mold follows. Lower indoor humidity in deep cold, run bath and kitchen fans, and keep furniture a few inches off cold exterior walls.
Attics and ice dams
Warm, moist air leaking into an attic condenses and freezes on the underside of the roof deck. When it thaws, it drips into insulation and ceilings. NOAA lists about 75 freeze-thaw cycles a year and a 50-year ground snow load of 40 pounds per square foot; heat escaping into the attic also melts snow that refreezes at the eaves, forming ice dams that push water under shingles. Sealing air leaks from the house into the attic and improving insulation and ventilation help with both.
Rain and leaks
NOAA lists a 100-year rainfall rate of 3.5 inches per hour. Water entering through the roof, windows or foundation needs to be dried within a day or two to keep mold from starting.
Testing
Visible mold doesn't always need testing. Testing can help when you smell mold but can't find it, or after cleanup to show it's done. Ask an inspector what they'll test and why, and be cautious if the same company tests and remediates.
Remediation
For anything bigger than a small patch, ask about containment to keep spores from spreading, removal of moldy porous materials, cleaning, and drying. Ask how they'll find and fix the moisture source. Get a written scope that lists rooms, materials and the containment plan, and ask whether clearance testing is independent.