How to Find Mold
Where to look and ways to uncover mold growth in your
home or building.
Important Note: If you find mold
growth, use the tips from the Mold
Clean Up page to protect yourself and to dispose of it
How you know if what you've
found is Mold
Any place that is dark, and where moisture
can accumulate, is a potential breeding ground for mold.
When mold grows within wall cavities (which
it often does) the nearby drywall is usually infected as well. If
toxic mold does become engrained in the
drywall, it should be replaced (after the mold is cleaned up
and the source of excessive moisture is resolved).
If your walls show signs of mold
(cracked/peeling paint, bulging behind the paint,
discoloration of walls), then that section of drywall should
be torn out and inspected. If the drywall is determined to
have mold (How you know if what you've found is
Mold), then follow the suggestions on the Mold
Clean Up page.
Behind Floor Baseboards
The space between the wall and the
baseboards serves as a great growing ground for mold. Since it
is a fairly sealed off space, it traps moisture. Plus, a lot
of dirt ends up here, providing the mold colonies with
plenty of nutrients to thrive.
If you suspect that you have a mold problem,
then you should be especially conscientious of the
basement or crawl space of your house. This level has more of a chance of
fostering mold growth than any other level in the home.
basements and crawl spaces, just look for any evidence of
dampness. Be especially aware of any black mold growth that might be
taking place in wooden building materials, especially
in the framing, since this is the best path for mold to
take to other parts of the home. It can also lead to the
weakening of beams and other bearing walls that are crucial in
the stability of the structure.
Any area where flooding, leaks, or other
types of water damage have occurred are prime candidates for
toxic black mold growth.
Rooms / Areas with High
If the relative
humidity in a certain room or area is commonly above 55%, then
over time, there is a strong likelihood a mold problem will
occur. In which case, it is important to monitor areas with
high humidity on a regular basis.
order to determine the relative humidity for a room or area,
you will need a relative humidity sensor (a.k.a. moisture
meter or hygrometer):
Humidity Sensor Buying Guide
Just as mold in the wall cavities can lead
to mold growth in interior walls, the same can happen in the
spaces above ceilings. Especially since a common source of
water infiltration - roof leaks - start from above.
you see any evidence of water damage or biological growth in
your ceilings, then you should investigate right away.
Beneath Bathroom/Kitchen Sinks
This is yet another place where moisture
is commonly a problem, and therefore another place where mold
can often be found.
The glue from the wall paper attracts
a lot of organic material (such as dust) that serves as a favorite
nutrient of mold.
Moist Window Frames
The window frame is in a position where warm
air commonly meets cold or cooler air, as a result of the
temperature difference outside and inside. This formula leads
to condensation, which leads to mold growth.
Look for biological growth in the seal where
the window frame meets the wall.
Inside Wall Cavities
This is another place where warm air
meets cooler air, especially the walls around the
perimeter of the home or building.
Plus, wall cavities are good at trapping
moisture. In addition to all this, pipes often leak in
between walls, where we are not aware they are occurring.
mold is present inside mold cavities, it will eventually
manifest its presence by working its way to the outside of the
walls, where it will be visible. If signs of excessive
moisture and mold begin to show on your walls, you can smell
the musty odor, and you or others in your home or building are
showing health effects from mold,
then it is likely growing in your wall cavities.
this is the case, then you will need to remove the drywall in
places where you suspect the mold is growing within the wall.
Then, you will need to clean and
remove the mold.
Excessive Moisture in Walls
Particle Board Material
This material is another desirable source of
nutrition for mold.
Fiberglass Insulation and/or
Backing and other Insulation Material
Mold does not live and grow on the
insulation itself. However, fiberglass and other types of
insulation collect a lot of dust and other organic
particulate. It is this dirt and grime that are able to make
insulation a nice home and breeding ground for mold.
Exposed insulation in the ductwork,
attacks, and basements/crawl spaces are most susceptible to
as moisture and dirt become trapped between walls and above
ceilings, they also become trapped beneath the floor. Tile
and carpet make great environments for mold since they
collect a lot of dust and other organics for mold to feed on.
Carpet can become especially ideal for mold growth since it
also holds in moisture.
In addition to the insulation (if present),
mold can grow in a variety of other places in the
ductwork/HVAC system. Other than the insulation, the two other
places mold is most likely to grow is the condenser or cooling
coil and the drain pan. In central air systems, these are
located in the air handler (by the fan).
The cooling coil cools the air that
comes into the system below the dew point, to remove the
condensation from the air. As a result, condensation builds up
on the coil itself, making it vulnerable to biological growth,
The drain pan
is located beneath the coil, and collects the condensation
that drips off the coil. Naturally, the water in the drain pan
can become the perfect environment for mold growth, especially
if the pan is not sloped. If it is flat, then the water will
become stagnant, increasing the likelihood of mold growth.
your system has an in-duct humidifier, then it can add
too much moisture into the ductwork. When this added moisture
combined with dirt and grime, mold can germinate in the ducts.
Growth in HVAC Systems
Evaporative Coolers (a.k.a. Swamp
Evaporative coolers increase humidity
in the home or building. They cool the air by evaporating
water (which has a cooling effect), then blow this air inside.
In which case, the air has an increased moisture
As a result, evaporative coolers increase
the potential for mold growth, especially nearby the unit.
The drain pan beneath the
refrigerator should be regularly checked for mold and other
types of microbiological growth.
The fact that plants need to be watered
regularly, and that the soil contains valuable
nutrients for mold, equals a haven for mold.
This is a sign that there is excessive
moisture within the wall, meaning that there could also be
mold growth nearby.
When this happens, track where the moisture
is accumulating. This can lead you to mold growth.
Between the dirt and grime we wash off
ourselves, and the water that can usually be found on shower
curtains, mold is often to be found as well.
|How you know if what
you've found is Mold
Black, grey-brown, grey-green, white & orange
spots, or even pink or purple
splotches if growing behind vinyl wallpaper. Stachybotrys
is commonly a dark, slimy, greenish-black mold.
By sending a sample of the biological
growth to a lab, they may be able to determine whether
it is mold, and what species of mold. You would need to
use a surface sampling technique that allowed the
species to be identified (Mold
Other Signs of
Signs of Mold
Once you find mold, then the next step is to
Clean and Remove the Mold.
You should also start employing methods to Prevent
further Mold Growth (prevent it as much as humanly
How to Clean Up a