On occasion, homeowners
may be stumped by the fungus problem - specifi-cally,
the growth of mushrooms on the underside of the sheathing
of their roof. According to U.S. Department of Energy
consultant Michael Lamb, the cause of this problem is
often starts with moisture leaking into the house through
the basement floor and walls. It is particularly frustrating
because the problem often becomes evident after the homeowner
has replaced older windows and weather-stripped the doors,
actions which usually improve the maintenance of a home.
Unfortunately, once a house is weatherized, moisture
can no longer escape through air leaks. These leaks are
shut tight - shutting in the moisture that is conducive
to the growth of various molds.
To control moisture in the basement, cover the floor
with 8-mil plastic from wall to wall. To assure coverage,
the homeowner should overlap the sheets by 3 to 6 inches,
then tape the seams. Place wooden planks where you need
to walk. Any loose mortar between the foundation stones
should be chipped out. The homeowner should repoint the
stones with hydraulic cement, then parge (cement skim
coat) the walls from the floor up to where the outside
grade begins. Apply two or three coats of latex-based
foundation waterproofing, which should help keep the basement
dry.
If homeowners want added protection against mushroom
growth, they can add roof vents, using aerosol foam caulk
to plug any holes leaking air into the attic. This is
just a secondary
measure, however; sealing the attic floor is much more
effective.
If theres already mold in the home, the homeowner
can kill it by
spraying it with a one to ten mixture of chlorine bleach
and
water. Use fans to ventilate the area to protect against
breathing in chlorine fumes. Dress appropriately and wear
a respirator.
To continue the prevention of mold growth, monitor the
homes humidity with several relative humidity (RH)
gauges. The RH should never exceed 45 percent. The RH
can be controlled with fans in warm weather and heat-recovery
ventilators in cold.
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