The Canada Mortgage Housing Corporation conducted a survey of 405 houses in
Ottawa, Canada, "to determine whether typical 'finished' basements are
contributing to poor indoor air quality as a result of mold growth in the
About half of
the 405 houses "had signs of moisture in the basement". The study
selected 22 for investigation. Molds were found in 18 of the 22 houses, or
82%. Samples were taken from 16 of the 18 houses. In 100% of those
houses, "molds with properties that are harmful to humans were found."
concluded: "1. Some finished basements do present health hazards to the
occupants due to the presence of toxigenic and dangerous molds in the wall
cavities; 2. The causes of mold growth in finished basements are directly
related to chronic wetting incidents rather than the wall finishing and
insulating techniques; and 3. The main chronic moisture sources
associated with mold growth in finished basements are exterior moisture
sources and wetting mechanisms."
For effective basement mold inspection, use a strong flashlight to check
100% of all wall, floor, and ceiling surfaces for mold growth, cracks in the
walls and floors, and water stains and other signs of water intrusion.
Use a professional model moisture meter to scan all walls, floors, and
ceilings for elevated levels of moisture, which, if found in one or more
locations, is strong evidence that water is coming into the basement through
the wall or floor area.
Use a digital hygrometer (about $30 from a hardware or home improvement
store) to check the basement humidity. Check humidity at different
times of the day and year-round and log into a humidity journal your
findings. If the indoor humidity is 70% or more, the high humidity alone is
sufficient to cause basement mold growth.
Is the land around the building
sloping away from the building (thus carrying rainfall and snow melt
away from the building) or toward the building (thus bringing excess water
to the building and causing possible water intrusion into the building's
foundation, concrete flood slabs, basement walls, and crawl space area)?
In addition, do
mold testing of the air in all of
the basement rooms and areas, and of the outward air flow from heating and
cooling duct registers to determine if there are elevated levels of airborne
mold consultants Phillip Fry and Divine Montero to find
air conditioning mold,
workplace mold, and mold hidden inside the walls, ceilings, floors,
crawl space, attic, basement, and HVAC equipment and system of your house,
condominium, office, workplace, or other building anywhere in Phoenix,
Mesa, and Scottsdale, Arizona, California, Las Vegas, USA, Canada, Hong
Kong, Malaysia, Singapore, Thailand, and elsewhere in Asia.
Mold Inspector Directory
Industrial Hygienist Training
Industrial Hygienist Directory
Mold Inspection Blog Questions & Answers
Basement mold growth caused by a leaking water supply pipe
in a home in Ontario, Canada. Picture taken Nov., 2011.
Basement wall mold growth caused by water coming through basement wall.
Mold Experts Recommend Frequent Inspection
and Removal for Mold-Prone Basements
Mesa, Arizona. April 29, 2013. Mold experts Phillip and Divine Fry
recommend quarterly or annual inspection and testing for basement mold
growth because basements often have the requirements for toxic mold growth,
especially ongoing high humidity and frequent water intrusion.
First, mold easily grows in building areas that are warm, damp, and poorly
ventilated such as basements and crawl spaces.
Second, mold-causing basement water intrusion can arise from multiple
problems such as dripping water lines and plumbing line leaks; high humidity
from the operation of washing machines and dryers (that are not directly
vented to the outdoors); burst water supply lines to the washing machine;
failed hot water heaters; clogged, failed, or under-sized sump pumps,
clogged or frozen sump pump discharge lines, and standing water in the sump
pump pit; window leaks; and water condensation caused by the large
temperature difference between the outside and the inside of basement wall.
In addition, water intrusion through basement walls and foundations is
common because of these four basement building defects: (a) cold joint
problems when the slab floor and foundation wall are poured at different
times, creating a small crack that can allow moisture to enter; (b)
foundation cracks in the vertical foundation walls can allow large
quantities of water to enter a basement; (c) cracks in the slab,
allowing pressure from the groundwater to force water up through the
concrete and into the basement; and (d) the absence or degradation of the an
effective water barrier beneath the concrete floor slab, thus allowing water
intrusion just like slab cracks discussed above.
Third, any water problem in the basement usually is slow to dry out because
the basement gets little or no sunlight, has high humidity (and thus the air
cannot absorb more moisture), and gets very little fresh air ventilation.
mold growth can go unnoticed for a long time since people don't spend much
time in their often poorly-lighted basements. People use their
to store many items that are good food for mold growth, such as cardboard
boxes to contain stored items. Homeowners do not regularly clean their
Fifth, Mold on basement walls can easily grow and spread into the floors and
walls above. Additionally, air born mold spores from the basement mold can
travel through the air to contaminate other areas of your home. The heating
and cooling system, generally located in the basement (where the mold is
present) provides an easy pathway to the entire house for airborne mold
For free mold advice on dealing with basement mold problems, email mold
consultant Phillip Fry
firstname.lastname@example.org or phone Mr. Fry 1-480-310-7970 and
1-480-217-7173 and visit the Frysí websites