Basement mold: why Adams County homes get it and what fixes it
Stone foundations, a high water table and finished basements are a bad combination. What actually stops it coming back.
Basements are where most mold calls in the Gettysburg area start. The reasons are local and predictable.
Why here
- Foundations. Borough houses from before about 1940 sit on stone or rubble foundations that let moisture through the walls. Post-war block foundations are better but not waterproof. Poured concrete is best and still sweats in summer.
- Water table. Low-lying parts of the borough and the townships along Rock Creek, Marsh Creek and the Conewago have a high seasonal water table. Sump pumps run for weeks in a wet spring.
- Humidity. Adams County summers are humid. A basement wall at 60°F with 75% relative humidity in the air above it will condense water on the wall surface every day.
- Finishing. Drywall, carpet and framing against a damp wall are exactly what mold needs. A bare block wall with a little efflorescence is ugly but harmless; the same wall behind drywall is a problem.
Surface mold or moisture problem?
Light grey or white fuzz on cardboard boxes and the bottom of furniture is a humidity problem: run a dehumidifier to keep the basement under 50% relative humidity, throw out the boxes, and it stops. Staining on drywall, a musty smell that does not clear, soft baseboards, or a tide line on the wall is a water problem, and the mold is a symptom of it.
What a lasting fix involves
- Water management outside. Gutters that discharge at least six feet from the foundation, grading that slopes away, window wells with covers. This is cheap and fixes more basements than anything else.
- Dehumidification. A proper basement dehumidifier, drained to the sump or a floor drain, set at 45 to 50%.
- Sump and drainage. A working sump pump with a battery backup; interior perimeter drains if the floor takes water.
- Removing what is wet. Any drywall, insulation or carpet that has been wet for more than 48 hours comes out. Framing can usually be cleaned and dried.
- Rebuilding differently. If you refinish, use moisture-tolerant materials against exterior walls and leave an air gap or use a dimpled membrane.
Who to call
For the mold and any wet materials, a remediation or restoration company from the directory. For the drainage and waterproofing, a basement waterproofing contractor; some of the restoration firms listed here do both, and their listing says so under crawl space and basement. For an independent opinion on how bad it is, a testing-only firm.
Last updated 2026-09-28. General information for the Gettysburg area, not professional advice; confirm specifics with a qualified contractor or your insurer.