Page 657 - 2018 National Home Improvement

2018 National Home Improvement Estimator, All Rights Reserved Page 528

Cleaning Methods
Non-porous materials (such as metals, glass and hard plastics) are easy to clean. Semi-porous
materials (such as wood, concrete, and masonry) should be cleaned if structurally sound. It's usually
better to discard more porous materials (such as ceiling tile, insulation and drywall). If you try to clean
drywall, keep cleaning at least 6 inches beyond where the board is discolored by mold. Before you
decide to clean the face of drywall, check the back side. The back may have a higher concentration of
mold than the front side.

Start breakout of what's to be discarded by misting the surface to minimize release of spores. Keep
using a HEPA vacuum to collect spores as work continues. Seal everything you remove in 6-mil plastic
bags while inside the containment structure. Wipe the exterior of each bag before removing it from
containment. Bag disposal doesn't require any special handling once bags are out of the building.

The best liquid for mold cleaning is a gallon of warm water mixed with two to four ounces of a
disinfectant-sanitizer. Again, mist the surface to minimize release of spores. Use a mister with a coarse
spray tip. Scrape any gross filth or heavy soil off the surface. Keep the surface moist for 10 minutes so
the disinfectant-sanitizer has time to work. Then wipe the surface clean using two buckets, the first with
plain water for rinsing and the second with the diluted disinfectant-sanitizer. Gentle cleaning helps
minimize release of spores. Clean beyond the area where you see signs of mold. When fully dry, go
over the area cleaned with a HEPA vacuum. Change filters as recommended by the manufacturer. Do
filter changes inside the containment area. Dispose of filters in sealed plastic bags.

Abrading (sanding and scraping) may be required on semi-porous surfaces. Where access is difficult,
such as in a crawl space or attic, blasting is usually more practical than sanding and scraping by hand.
It might take 120 manhours to sand and scrape a mold-infested attic. Blasting could reduce the labor by
half.

Blasting done with sand, glass beads or bicarbonate of soda leaves a residue which has to be cleaned
up with a HEPA filter vacuum. You'll need both an air source and a scrubber when blasting inside a
containment structure. Blasting with dry ice leaves much less residue. Dry-ice pellets are soft. They
don't scratch the surface as much as other blasting materials. Instead, sudden cooling makes the mold
easy to flake off. The dry ice simply evaporates, leaving no chemical residue.

Regardless of the cleaning method, some mold residue will remain on semiporous surfaces such as
concrete, masonry or framing. Once the surface is clean and dry, encapsulate any mold that remains
on the surface with an anti-microbial coating, either by brush, roller or spray.

When done with the containment structure, run a damp cloth or sponge mop over the entire interior,
including the airlock. When dry, vacuum the interior with a HEPA vacuum. Dispose of the containment
structure's poly sheeting and air lock in 6-mil bags. The entire area should be left dry and visibly free
from mold, dust and debris.