Charlie,
Black mold mitigation companies follow three steps when a house has black mold that must go.

1. Find out where water is entering the space, then plug/patch/divert/cap the source. Black mold thrives in cool, dark places where lots of water raises the humidity. Typically a buried basement.

2. Demolish and scrap-out any studs, drywall, and insulation that is infected with mold. Some houses just need the carpet ripped out of a rec room, and a circular saw for cutting away the bottom 3' of drywall; I am helping a couple buy a home that has mold on the drywall from floor to ceiling, so ALL of the carpet, studs, drywall, insulation will be removed.

3. Spray a series of EPA-mandated chemicals on any remaining mold on concrete walls and floors, to kill it, then rinse the mold and spores away and remove the liquid that flushed away the mold from the house. The infected areas are now sanitized. A final coat of chemicals that create a hostile environment for mold is sprayed to prevent future mold growth.

All three steps above are the most effective way to stop the water source, remove infected finish material, then kill the mold on the foundation, slab, and joists.

Your long-term insurance against future mold infection in that space will be Step 1. Do whatever it takes to stop water from entering that space.

My parent's 43 year-old house in Mt Vernon got black mold in the basement last year. Mid-Atlantic inspected the space. The problem they found was the foundation's interior perimeter of old clay pipes buried in a bed of gravel under the concrete slab does what all of that old clay pipe does over 40+ years... it softens and it collapsed.

For folks who have a 40+ year-old house with a sump pump in a sump crock buried into the soil under the basement concrete slab, the perimeter of clay pipe in gravel that runs in a loop around the foundation footers beneath the slab is there to collect water that collects beneath the slab, channels the water to the sump crock, where the pump flushes the water up to a pipe that dumps the water out into your yard.

Builders switched from clay pipe to black plastic corrugated pipe that has 4-6 holes 1/2 inch diameter holes to collect water that weeps under the slab, divert it to the sump crock to be pumped up and out int the yard. That black plastic lasts forever, maintenance-free, until the end of time.

Erick Blackwelder
Exit 1st Choice Realty
Over 2,000 Nice Folks Like You Helped Sell Or Buy A Home
703-590-2252