Attic
- Observe the sheathing (roof deck) and rafters with a strong flashlight. Sample representative discolorations and nearby clean-appearing areas.
- Sample the sheathing if there appears to be a dark sheen over it.
- Look for signs of white or green mold where the rafters meet the sheathing.
- Do a couple of tapes on various wood surfaces.
- If there are gable vents, observe the area for discolorations.
Living areas
- Check inside sink cabinets, near the plumbing.
- Check access holes to bathtub fixtures.
- Were there any past plumbing or roof leaks that might call for investigation in a particular area?
- Are there any antiques, used furniture, or books bought in a garage sale that smell musty or might be moldy?
- Without making a hole in the wall, often you can get a clue whether mold might be present behind the wall by testing at the bottom of the base mold. Put tape over the tip of your finger, and get your fingernail into the crack between the bottom of the molding and the floor. Tape-test a few spots at the bottom of the molding.
- If water penetrated onto a top floor ceiling from an ice dam, but the ceiling was never opened up, there is potential for hidden mold on the other side of the ceiling. Decide if you want to make a test hole to check (see cautionary comment below). (There is the potential for Stachybotrys if the ceiling is drywall.)
- If the house seems damp, spot-check upholstered furniture, both on upholstered part and (separate tape) on unfinished wood surfaces.
- In a damp house, check inside closets, at the back at the bottom edge of base molding.
- Sometimes mold shows up on carpeting.
HVAC (heating, ventilation, and air conditioning)
- Take off a vent cover and sample inside the vent, preferably from the sides and top of the air duct. If you sample on the bottom, there may be a lot of debris on the tape. If sending samples to EnviroHealth for screening, include a tape from the bottom of the air duct. I can culture that and see what grows.
- Using a strong flashlight, examine the AC coils for signs of mold growth. Sample as needed.
- Examine the filter. The best kind are pleated media, like an accordion pleat. Make sure there is a good fit so that dirty air doesn't by-pass the filter. You might even put tape over the edge of the filter so that room air isn't drawn into the unit. Take a tape sample from the dirty side of the filter. If sending samples to EnviroHealth, send two tapes, one for culturing (no extra charge).
- Look for signs of leakage at pipes and at the drainage pan. Sample as needed.
Caution: Again, do not use Magic Tape or other cloudy tape, or the light from the microscope will not pass through the tape. I use 3/4" Scotch-brand MultiTask tape (or similar tape) for testing. You can find this in an office supply store.
|
| Basement and/or crawlspace
Here are general questions for an unfinished basement and/or crawlspace:
- Sample on the underside of the steps. The amount of Aspergillus growth gives me a clue as to the risk of mold in the rest of the area. I use the steps as a marker.
- Is mold growing (and how much mold is growing) on unprotected wood, such as the subflooring and ceiling joists, a work table, the wood backing of the electric box, pressed wood shelves, stored possessions, etc.
In a finished basement, I'm interested in these issues:
- Is mold growing on furniture and other possessions?
- Is mold growing behind finished walls?
- Is mold growing above a drop ceiling?
Tips:
- Mold grows faster on softer cellulosic surfaces than on shiny or finished cellulosic surfaces. For example, mold would grow on dull wicker faster than on shiny wicker , faster on upholstery and unfinished wood than on finished surfaces of wood., and faster on dull cardboard boxes than on shiny cardboard boxes.
- If mold is growing on surfaces in the basement, stray spores are likely in the air and in dust. A dust sample tape could provide a clue as to the numbers of mold spores in the air. If there is a lot of debris on the tape, send two tapes to EnviroHealth, one for culturing.
- Mold can grow on organic debris on concrete. Tape samples can be sent from concrete, but the general approach to cleaning would be HEPA vacuuming and then scrubbing off with Borax solution. Take steps to reduce moisture intrusion from the exterior as needed.
- Basement and crawlspace ceilings may have fiberglass insulation between the joists. If this fiberglass insulation was present from the time of construction, it may have protected the surfaces it covers from mold. If checking behind the fiberglass insulation, wear an N95 respirator and goggles. Use a stick to gently push the fiberglass aside so that you can tape-sample. Wash your hands afterwards. It's hard to work with sticky tape when wearing gloves.
Mold doesn't grow in fiberglass insulation but it can grow on dust in the insulation. In my experience, most of the dirty-looking areas in fiberglass insulation are exactly that - dirt, soot, dust. It's still worth doing a tape test on the insulation to rule out mold.
Samples:
- Ceiling joists
- Subflooring (deck of floor above)
- Underside of steps, near floor
- Behind finished wall near floor - try to access from an unifnished room, such as a utility room. Sample the paper backing of drywall, the back of paneling, as well as the sill plate and the lower part of studs.
- Furniture and stored possessions
- Carpet, if present. Basement carpeting raises the risk for mold growth unless you live in a desert.
Top of page
|
