Black mold removal in Cary, NC

What people mean by black mold

“Black mold” usually refers to Stachybotrys chartarum, a slimy, greenish-black mold that has a reputation as the dangerous one. In practice, the dark spots people find on walls, ceilings and window sills are often other common molds, such as Cladosporium, Alternaria or Aspergillus niger, all of which can look black or dark green. Telling them apart takes a lab. For deciding what to do, it rarely matters: dark growth on building materials means something stayed wet, and it all gets removed the same way.

Why Stachybotrys points to a long-term leak

Stachybotrys is a slow starter. It needs very wet conditions that last, which is why it shows up on drywall paper, ceiling tiles and cardboard that stayed damp for days or weeks, rather than on a surface that got splashed once. Finding it is a strong hint of an ongoing leak or a past water event that was never dried, often inside a wall cavity or under a floor where no one could see it.

Black mold and health

Mold can cause stuffy nose, throat irritation, coughing or wheezing, eye irritation and skin irritation in sensitive people, and reactions are more serious for people with allergies, asthma, chronic lung disease or weakened immune systems. The CDC notes that reports linking toxic molds in homes to rare conditions are few, and that a cause-and-effect link has not been proven. The practical takeaway is the same for any mold: do not live with it, and do not disturb a large area without protection. If someone in the house has symptoms, talk to a doctor.

Where dark mold grows in Triangle houses

• Behind and under bathroom vanities and kitchen sinks, from slow drain leaks.
• On the drywall behind a leaking shower valve or a failed tub surround.
• On ceilings below an attic air handler whose drain pan overflowed.
• Behind washing machines and refrigerators with ice maker lines.
• On exterior walls behind furniture, where condensation forms in cold weather.
• On window sills and frames that sweat in winter.
• On the lower part of walls after a flood or overflow that was not dried properly.

How black mold is removed

The process is the same as any mold remediation, scaled to the size of the area. The moisture source is found and fixed. For anything larger than a small patch, the area is sealed off with plastic and kept under negative air with HEPA filtration. Moldy drywall is cut out with a margin beyond the visible growth, bagged inside the containment and carried out sealed. The framing behind it is HEPA vacuumed, cleaned and dried, the area is cleaned again, and it is checked before rebuilding.

Why the back of the drywall matters

The spots on the room side of a wall are often the smallest part of the problem. Growth on the back of the drywall, on the insulation and on the bottom plate can be several times larger, because that is where the water sat. That is why black mold on drywall is cut out rather than cleaned, and why a crew opens the wall a little beyond the visible edge.

Clean it yourself or call?

EPA guidance says homeowners can usually handle mold covering less than about 10 square feet, roughly a three-by-three-foot patch, on hard surfaces, with gloves, goggles and an N95 respirator. Larger areas, mold on drywall that needs cutting out, mold in heating and cooling systems, mold after sewage or flood water, and situations involving people with health concerns are better left to professionals. The guide to cleaning up mold yourself explains what is safe. If you are not sure what the dark spots are, a mold inspection with a surface sample will tell you.