Mold Facts You Should Know
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Questions? Call Us At 1-866-938-6487
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| What causes mold to develop?
Mold requires nutrients, water, oxygen and favorable temperatures
to grow. Nutrients for mold are present in dead organic material such
as wood, paper or fabrics; mold can also derive nutrients from some
synthetic products such as paints and adhesives. Mold requires
moisture, although some mold species can obtain that moisture from
moist air when the relative humidity is above 70 per cent. Many molds
thrive at normal indoor temperatures; few if any molds are able to
grow below 40 F or above 100 F. Outside this range molds may remain
dormant or inactive; they may begin to grow again when the temperature
is more favorable. Temperatures well above 100 F will kill mold and
mold spores, but the exact temperature required to kill specific
species is not well established. |
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How does mold get into a building?
Molds are decomposers of organic material such as wood, plants and
animals. Mold and mold spores are found in high concentrations
wherever there is dead matter such as a pile of leaves, manure or
compost. Mold spores enter buildings through the air or on people,
animals and objects that are brought into the building. Spores are
small bundles of genetic material and chemicals (similar to seeds)
that molds make under certain conditions. |
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Are there harmful and non-harmful molds?
There are only a few molds that can cause infection in healthy
humans. Some molds cause infections only in people with compromised
immune systems. The biggest health problem from exposure to mold is
allergy and asthma in susceptible people. There are more than 100,000
types of mold. Good information has been developed for only a small
number of these molds – at least in terms of their effects on human
health. Most people tolerate exposure to moderate levels of many
different molds without any apparent adverse health effects.
Some molds produce powerful chemicals called “mycotoxins” that can
produce illness in animals and people. Scientific knowledge about the
health effects of these toxins on humans is quite limited. |
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| Does mold affect everyone the same way?
No. Some individuals have a genetic makeup that puts them at risk
for developing allergies to mold. People who have an allergy to mold,
especially if they also have asthma, can become ill from exposure to a
small amount of mold. Individuals also seem to be quite different in
their response to exposure to the toxic chemicals that some molds
release. These differences between individuals contribute to the
difficult question of determining safe exposure limits for mold. |
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| How much mold exposure is harmful?
Each person’s personal exposure level is different and the United
States does not have a standardized threshold for exposure.
Individuals are very different with respect to the amount of mold
exposure they can tolerate. Children under the age of one, year may be
more susceptible to the effects of some molds than older individuals.
Measuring or estimating "exposure" levels is very difficult.
“Exposure” means the amount of mold (microscopic spores and mold
fragments) that gets into a person usually by breathing, but also by
eating or absorption through the skin. For example, a building may
have a lot of mold in the walls but very little of that mold is
getting into the air stream. In that case the people working or living
in that building would have little mold exposure. |
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| Can mold exposure cause brain damage or
death?
Some “experts” claim that individuals have brain damage or have
died because of exposure to mold and especially mold toxins. Although
much discussion surrounds this issue, judges and juries have been
convinced that this is true and have awarded large settlements as a
result. The prudent course of action would be to limit one’s exposure
to really moldy environments. By “really moldy” we mean where there
are large visible areas of mold (more than a few square feet) or the
building has a “musty” odor because of hidden mold growth. There are
many epidemiological studies showing that people who live in houses
with dampness have many more health problems, especially respiratory,
than do people who live in dry houses. This association does not
“prove” that it is the mold that is responsible for the increase in
illness. However, it does support the assertion that it is not wise to
live in damp, moldy buildings. |
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| Does tighter building construction promote
mold development?
Tighter building construction does not by itself promote mold
growth, but tight construction combined with some poor choices in
design, building materials or operations can increase the probability
of mold growth. What do we mean? The tighter the building construction
the less air exchange there is between the inside air and the outside
air. Whatever gets into the inside air stays there longer than it
would in a house with loose construction. Moisture that gets into the
air from activities such as cooking, bathing and even breathing will
remain in a tight house longer than it would in a loose house. That’s
why exhaust fans should be installed in bathrooms and kitchens and
vented to the outside. Clothes dryers should also be vented to
the outside.
Tight construction permits control of the air exchange between the
inside and the outside and can prevent the deposition of moisture in
walls and roofs. Controlling moisture, including indoor relative
humidity is the key to preventing mold growth. Tight building
construction when combined with source control of moisture (exhaust
fans) and controlled ventilation (intentional introduction of outside
air) reduces the probability of mold growth in a building. Controlled
ventilation can be provided by a duct that brings outside air to the
return side of the air handler of a forced air system. A timing device
or fan cycler can be programmed to have the air handler turn on for a
specified number of minutes each hour even when there is no call for
heating or cooling. In cold climates controlled ventilation is
frequently provided by a heat recovery ventilator (HRV). |
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| Do new building materials (e.g. drywall or
paper faced gypsum board) promote mold
growth?
Mold needs water, a nutrient source, oxygen and favorable
temperatures to grow. Many species of mold love paper faced gypsum
board. Why? Making paper involves the mechanical and chemical
processing of wood. Paper is largely pre-digested so it is easy for
mold to get nutrients from the paper. But unless there is enough
moisture present mold can’t grow on the paper. If paper faced gypsum
board is kept dry, it can be used and still not have mold. This
material is kept dry by controlling the interior relative humidity,
keeping rain from entering roofs and walls, and NOT using paper faced
gypsum in areas that are likely to get wet. This means no paper
faced gypsum board in shower and tub areas. Cement board, mortar or
non-paper faced gypsum can safely be used in these damp areas because
these products do not contain nutrients to support mold growth. |
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| Are there reliable tests to indicate the
presence of mold?
Almost all of us already have two effective mold detectors: our
eyes and our noses. If black or green discoloration is noticed that is
fuzzy in appearance and is in a location that is damp or had been
damp, it is almost certainly mold. If a building smells musty, there
probably is mold somewhere; the mold may be on boxes stored in a
basement or in walls or in the crawl space. If you want to find mold,
look for the presence of water or a location where water was likely to
have been. If there is still any question about whether the black
stuff is mold, have a reliable laboratory examine the material. All
you need to know is whether mold is seen when the material is examined
under the microscope.
Surface and/or air sampling for mold should be done to obtain an
answer to a question that cannot be answered without the test(s).
While real estate agents, lawyers, governments and homeowners often
like to no what’s floating around in their air, we can tell you that
as a general rule the Center for Disease Control (CDC), the U.S.
Environmental Protection Agency (EPA) and the American Conference of
Governmental Industrial Hygienists do not recommend routine air
testing for mold. Each case is different and a reputable environmental
consultant will be able to advise if you should have a sampling survey
done. |
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| If mold is present, what’s the best way to
get rid of it?
The answer depends on how much mold is present and where it is
located. If the mold is on furnishings or boxes simply discard the
materials. Moldy materials are not considered hazardous waste; they
can be sent to a regular landfill. However, it is smart to seal the
moldy material in heavy plastic to protect the people who handle it in
transit and prevent spreading large amounts of the mold into the
building as you carry the material out of it.
If the mold is on a hard surface but occupies less than 10 square
feet wash and/or scrub the area with soapy water (contrary to popular
belief do not use bleach) rinse and allow the area to dry before
repainting. If you have asthma, severe allergies and a weaken immune
system get someone else to do the clean up.
Larger areas (greater than 10 square feet in area) should be
cleaned by a professional who has experience doing this type of work.
Remember, determine what caused the moisture problem and correct that
problem. A competent environmental consultant will advise you not only
on the correct way to clean it up, but why it is there in the first
place. |
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| Is it possible to completely eliminate
mold from the inside of a home or
office building?
The answer is basically no. As mold exists naturally in the
environment it would be virtually impossible to eliminate all mold
spores in your home or office. To keep a building completely free of
mold spores requires very efficient air filtration and is only
accomplished in special situations such as hospital operating rooms
and manufacturing “clean rooms.” Remember, mold spores are microscopic
and in the outside air virtually all the time. Some will get inside
your home or office.
However, it is possible to keep mold from growing inside a
building. Moisture control is the key to controlling mold in interior
spaces. Air filtration can contribute to lowering mold spores in the
air but is secondary to moisture control. |
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| Should I use bleach to get rid of mold?
No. Although bleach can kill and decolorize mold, it does not
remove it. Dead mold can still cause allergic reactions. It is not
necessary to kill mold to remove mold. Soap and water and scrubbing
can remove mold from hard surfaces. The Environmental Protection
Agency (EPA), the
Center for Disease Control (CDC)
and the New
York City Health Department agree that bleach or other biocides
should not routinely be used to clean up mold. |
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| How do I know when the mold clean up is
finished?
The mold cleanup is finished when there is no visible mold
remaining and there is no dust or dirt remaining that could contain
large amounts of mold and mold spores. Routine clearance testing for
mold may or may not be required. Leaving a few mold spores behind is
usually not a problem if the underlying
moisture problem has been corrected. Remember that mold
spores are virtually everywhere. Even if all mold and mold spores are
removed as part of the cleanup, spores from outside will re-enter that
space. The spores won’t be able to grow unless water is also present. |
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| Where can I find more information on mold?
The EPA is a good
source for more information about mold.
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