Got
Mold?
As home inspectors, we see mold growing in all sorts of places. A few years
ago our clients started asking if we would collect samples for laboratory analysis
to determine if the molds were "toxic." After extensive research into
mold-related problems, we decided to help our clients by collecting samples
when they want them, but also to help determine the causes of the mold,
and to develop effective solutions. The purpose of this article is to provide
a background to potential problems relating to molds and excessive moisture,
and to offer a few solutions. Keep in mind that water problems that may not
be visible to the inspector will most likely show up with air quality testing.
Historically, mold issues have been addressed primarily in the commercial
sector by specially trained industrial hygienists, who use a wide range of
skills and techniques to solve indoor air quality (IAQ) problems found in
office buildings and other large structures. Molds and problem air quality
issues have recently become much more apparent in homes, creating the need
for a new approach.
First, the Basics
A mold is a type of fungus. Molds grow everywhere and can be found in some
amount in every room or space. If you can see mold or if you notice an earthy
or musty odor, you can assume there is a potential mold problem. Molds need
a food source to live and tend to grow on porous cellulose materials such
as wood, ceiling tiles, and sheet rock or gypsum board. Molds especially like
dry wall or sheet rock because it is porous and contains nutrients the molds
can feed on.
Molds can also grow on hard surfaces, such as tile or metal window frames-or
even glass-by living on the dust that sticks to cool, damp surfaces. These
areas are easy to clean with household detergent.
There are three primary ways molds can cause harm.
Molds can be toxic, infectious, or allergenic. Molds that produce mycotoxins
such as Stachybotrys and Trichoderma are considered "toxic molds,"
and are thought by some to present a greater hazard than common molds such
as Cladosporium and Alternaria. Our research shows that Penicillium-Aspergillus
molds are most likely to cause allergy or asthma-related problems in homes.
The popular term "toxic mold" is considered by many experts to be
incorrect or even misleading.
Toxicity is based on dosage.
Any substance is toxic if ingested in sufficiently large quantities (including
coffee, tea, or even pure water). While a specific mold would be toxic if
ingested or inhaled in large quantities, such exposures appear to be rare.
Mycotoxins are toxic substances produced by molds. Mycotoxins often adhere
to surfaces and do not easily become airborne where they can be inhaled in
quantities sufficient to create a toxic effect.
Some fungi, such as Aspergillus and Fusarium, can cause infectious diseases.
Most infectious diseases caused by fungi occur in individuals who are immune-compromised,
such as those with severe burns or HIV; those hospitalized for cancer treatment;
and individuals who have lung diseases. People with other respiratory illnesses,
the elderly, and infants are also vulnerable to infectious molds. The immune
system of a healthy person can easily ward off many infectious attacks, although
fungi from bird or bat droppings can cause a flu-like illness even in healthy
individuals.
Allergenic molds are much more likely to cause problems for
humans. Mold allergies are not uncommon and are routinely diagnosed by allergy
specialists. Mold spores are inhaled into the lungs with almost every breath
we take and those of us who are highly sensitive to molds, dust, dust mites,
and other minute particles need to take special care to maintain a healthy
indoor environment.
Mold Sources
Significant mold growth does not occur unless there is sufficient moisture,
typically caused by excessive air humidity, water entry, or plumbing leaks.
Excessive humidity caused by poor ventilation after bathing, showering, boiling
water, cooking, and other moisture-producing activities are the primary sources
of mold growth in the home. Improperly installed windows, leaky roofs, moist
or damp basements, and excessively damp subfloor areas can contribute to high
moisture and interior mold growth.
There are numerous ways to test for mold, and no single method is effective
for each situation. Mold can grow inside walls, in building materials, and
in those areas that are not routinely occupied. Mold spores may not show up
in air sampling tests if they are not airborne at the time of sampling.
Primary Sampling Techniques
Outdoor Air Samples establish a base reading.
Indoor Air Samples determine relative mold spore concentration in the air.
Swab Sample: A swab is wiped on a surface to collect mold samples.
Tape Lift:A strip of tape is used to collect the sample. The tape is placed
on a glass slide for microscopic examination.
Carpet Sample: Tape is used to collect a sample from the carpet surface, or
a sample is vacuumed from an area of carpet.
Wall Cavity Sample: Air is drawn through small holes drilled in the wall and
sampled for spore activity.
Duct Test: Dust from furnace ducting or filters is sampled and tested.
How many samples should be taken?
A minimum of two to three different type samples is usually necessary to determine
if the number of mold spores inside a home is significantly elevated at the
time of our review. Conditions that produce high spore counts in the air will
change throughout the day depending on occupants' activities.
How soon will we get results?
Most labs provide a three to five day turn-around. Results can be obtained
within 48 hours for an extra fee.
How much will this cost?
$125.00 per air sample, (minimum of two) and $125.00 per swab or slide sampling
if necessary, if done in conjunction with a home inspection.
We discount this fee by $100 if the inspector is already on-site to provide
other services, such as a home inspection.
The Bottom Line
It is important to keep indoor spaces well ventilated and relatively dry.
If you have reason to believe that you or others in your family are especially
sensitive to molds, and if you see mold or smell musty odors, you should consider
having samples collected and sent to an approved laboratory for analysis.
Our inspectors have extensive experience locating and solving problems related
to excessive moisture in homes and commercial properties.
At ACCU-Home Inspections, it is our goal to provide the best sampling available..
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