MOLD QUESTIONS - BUT WITHOUT ALL THE
What percentage of mold inspections end up killing transactions?
Very few actually. The truth is:
• Most inspections end in favorable results for all concerned.
• Mold is everywhere and most indoor air tests end up no different than
• Most molds that are detected are not toxic.
• Most mold removal jobs are minor and able to be performed by
How does mold 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; from wet construction materials including wood, concrete,
drywall, carpet or wallpaper; and from some synthetic products such as
paints and adhesives.
How does mold get into a building?
Mold typically enters a building one of two ways;
Most often mold develops as the result of water intrusion from a flood,
leaky pipe, or condensation. Unless water intrusions are effectively dealt
with within 48 hours of occurrence, ensuing mold issues are almost certain.
The problem is, most small plumbing leaks and condensation issues go
undetected until mold becomes a problem. Even so, most mold problems are
easily and inexpensively resolve in early stages.
The second most common way mold enters buildings is through the air or on
people, animals and objects that are brought into the building.
How does mold
Surface molds spread by eating everything they come in contact with. When
surface molds are disturbed they produce mold spores, which become airborne.
Airborne mold spores are (similar to seeds), they reproduce more spores.
Another requirement for mold to grow is moisture, although some mold species
can obtain that moisture from moist air when the relative humidity is above
70 per cent.
Can you see airborne mold spores?
Only under a microscope. 250,000 spores can fit on the head of a pin. They
are so light they will stay airborne as long as 8 hours in a room with zero
Can you smell airborne mold spores?
Mold spores are known to produce the same musty odors as surface molds.
Are there harmful and non-harmful molds?
There are more than 100,000 types of mold. Only a few of them can cause
infection in healthy humans (emphasis on “healthy”), while other molds cause
infections only in people with compromised immune systems. Most people
tolerate exposure to moderate levels of many different molds without any
apparent adverse health effects, while others may have severe allergic
reactions to the slightest amounts.
Some molds produce powerful chemicals called "mycotoxins" that can cause
illness in animals and people. Scientific knowledge about the health effects
of these toxins on humans is quite limited.
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. Those most susceptible mold-borne illness are infants with under
developed immune systems, elderly with weakened immune systems, AIDS and
cancer patients, anyone whose immune system has been compromised by
respiratory infections such as pneumonia, bronchitis, etc., and people who
undergo harsh medical treatments such as chemotherapy.
How much mold exposure is harmful?
No one knows the answer to this question for several reasons. Individuals
are very different with respect to the amount of mold exposure they can
tolerate. 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, even though the building itself is deteriorating.
Can mold exposure cause brain damage or death?
Although some "experts" claim that individuals have brain damage or have
died because of exposure to mold and especially mold toxins, there is no
verifiable scientific or medical proof at this time to support these claims.
Consequently it is prudent to minimize 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.
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
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).
Do new building materials (e.g. drywall or paper faced gypsum board) promote
Mold needs water, a nutrient source, oxygen and favorable temperature 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.
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 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.
Typically, mold testing is done either by extracting a sample from a suspect
surface, or by extracting samples of the air. Both methods are accurate when
analysis is preformed properly by a qualified lab.
Is it necessary to perform sample testing with every inspection?
It depends what the objective is. If the objective is simply to locate mold
and identify its source, the answer is no. Once the source of mold is
identified, air sampling does not provide additional meaningful information.
Conversely, if the objective is to determine the types and/or amounts of
mold present, the answer is yes. Air sampling provides a wealth of
information and is the only reliable way to get a “snapshot” of the indoor
air quality at the time the testing occurred.
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 mold 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
the area with and anti-fungal mildewcide (scrubbing with a brush may be
necessary), then dry the area with commercial grade dehumidifiers before
repainting. If you have asthma, severe allergies and a weaken immune system
get someone else to do the clean up. In all situations, wear protective gear
including rubber gloves, a respirator and face shield.
Larger areas (greater than 10 square feet in area) should be cleaned by
someone with experience in doing this type of work. Remember, determine what
caused the moisture problem and correct that problem. Otherwise, mold is
likely to recur.
Is it possible to completely eliminate mold from the inside of a home or
The answer depends upon what is meant by "completely eliminate mold." 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
in the outside air virtually all the time and some of them will get inside
buildings. 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.
Should I use bleach to get rid of mold?
No. Although bleach will kill and decolorize mold, it does not remove mold.
Dead mold can still cause allergic reactions and can resurrect itself under
the right conditions. The Environmental Protection Agency (EPA), the Center
for Disease Control (CDC) agree that bleach or other biocides should not
routinely be used to clean up mold. Only anti-microbial, anti-fungal,
mildewcide cleaners should be used.
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 is not always necessary
but may be required in some instances. Leaving a few mold spores behind is
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