What is Mold? Molds are fungi. Molds grow throughout the natural
and built environment. Tiny particles of mold are present in indoor
and outdoor air. In nature, molds help break down dead materials
and can be found growing on soil, foods, plant matter, and other
items. Molds produce microscopic cells called "spores"
which are very tiny and spread easily through the air. Live spores
act like seeds, forming new mold growths (colonies) when they find
the right conditions.
What does
mold need to grow?
Mold
only needs a few simple things to grow and multiply:
- Moisture
- Nutrients
- Suitable
place to grow
Of these, controlling
excess moisture is the key to preventing and stopping indoor mold
growth.
Should I
be concerned about mold in my home? Mold should not be permitted
to grow and multiply indoors. When this happens, health problems
can occur and building materials, goods and furnishings may be damaged.
Health
Effects
Can mold
make me and my family sick?
Mold can affect the health of people who are exposed to it. People
are mainly exposed to mold by breathing spores or other tiny fragments.
People can also be exposed through skin contact with mold contaminants
(for example, by touching moldy surfaces) and by swallowing it.
The type and
severity of health effects that mold may produce are usually difficult
to predict. The risks can vary greatly from one location to another,
over time, and from person to person.
What symptoms
might I see?
The
most common health problems caused by indoor mold are allergy symptoms.
Although other and more serious problems can occur, people exposed
to mold commonly report problems such as:
- Nasal and
sinus congestion
- Cough
- Wheeze/breathing
difficulties
- Sore throat
- Skin and
eye irritation
- Upper respiratory
infections (including sinus)
Are the risks
greater for some people?
There is wide variability in how different people are affected by
indoor mold. However, the long term presence of indoor mold growth
may eventually become unhealthy for anyone. The following types
of people may be affected more severely and sooner than others:
- Infants and
children
- Elderly people
- Individuals
with respiratory conditions or sensitivities such as allergies
and asthma
- Persons having
weakened immune systems (for example, people with HIV infection,
chemotherapy patients, organ transplant recipients)
Those with special
health concerns should consult a medical professional if they feel
their health is affected by indoor mold. Are some molds more
hazardous than others?
Some types of
mold can produce chemical compounds (called mycotoxins) although
they do not always do so. Molds that are able to produce toxins
are common. In some circumstances, the toxins produced by indoor
mold may cause health problems. However, all indoor mold growth
is potentially harmful and should be removed promptly, no matter
what types of mold is present or whether it can produce toxins.
Home
Investigation
How
do I tell if I have a mold problem?
Investigate, don't test. The most practical way to find a mold problem
is by using your eyes to look for mold growth and by using your
nose to locate the source of a suspicious odor. If you see mold
or if there is an earthy or musty smell, you should assume a mold
problem exists. Other clues are signs of excess moisture or the
worsening of allergy-like symptoms.
Look for visible
mold growth (may appear cottony, velvety, granular, or leathery
and have varied colors of white, gray, brown, black, yellow, green).
Mold often appears as discoloration, staining, or fuzzy growth on
the surface of building materials or furnishings. When mold is visible,
testing is not recommended.
- Search areas
with noticeable mold odors.
- Look for
signs of excess moisture or water damage. Look for water leaks,
standing water, water stains, condensation problems. For example,
do you see any watermarks or discoloration on walls, ceilings,
carpet, woodwork or other building materials?
- Search behind
and underneath materials (carpet and pad, wallpaper, vinyl flooring,
sink cabinets), furniture, or stored items (especially things
placed near outside walls or on cold floors). Sometimes destructive
techniques may be needed to inspect and clean enclosed spaces
where mold and moisture are hidden; for example, opening up a
wall cavity.
Should I
test for mold?
We do not recommend testing for mold yourself. Instead, you should
simply assume there is a problem whenever you see mold or smell
mold odors. Testing should never take the place of visual inspection
and it should never use up resources that are needed to correct
moisture problems and remove all visible growth.
Sometimes, mold
growth is hidden and difficult to locate. In such cases, a combination
of air (outdoor and indoor air samples) and bulk (material) samples
may help determine the extent of contamination and where cleaning
is needed. However, mold testing is rarely useful for trying to
answer questions about health concerns.
Mold
Clean-up and Removal
To clean up and remove indoor mold growth, follow steps 1-6 as they
apply to your home.
- Identify
and Fix the Moisture Problem -
the most important step in solving a mold problem is to identify
and correct the moisture sources that allowed the growth in the
first place. Common indoor moisture sources include:
- Flooding
- Condensation
(caused by indoor humidity that is too high or surfaces that
are too cold)
- Movement
through basement walls and slab
- Roof
leaks
- Plumbing
leaks
- Overflow
from tubs, sinks, or toilets
- Firewood
stored indoors
- Humidifier
use
- Inadequate
venting of kitchen and bath humidity
- Improper
venting of combustion appliances
- Failure
to vent clothes dryer exhaust outdoors (including electric
dryers)
- Line
drying laundry indoors
- House
plants - watering them can generate large amounts of moisture
To keep indoor
surfaces as dry as possible, try to maintain the home's relative
humidity between 20-40 percent in the winter and less than 60
percent the rest of the year. You can purchase devices to measure
relative humidity at some home supply stores. Ventilation, air
circulation near cold surfaces, dehumidification, and efforts
to minimize the production of moisture in the home are all very
important in controlling high humidity that frequently causes
mold growth in our cold climate.
- Begin
Drying All Wet Materials - as soon as possible, begin drying
any materials that are wet. For severe moisture problems, use
fans and dehumidifiers and move wet items away from walls and
off floors. Check with equipment rental companies or restoration
firms to see if you can rent fans and dehumidifiers.
- Remove
and Dispose of Mold Contaminated Materials - items which have
absorbed moisture (porous materials) and which have mold growing
on them need to be removed, bagged and thrown out. Such materials
may include sheet rock, insulation, plaster, carpet/carpet pad,
ceiling tiles, wood products (other than solid wood), and paper
products. Likewise, any such porous materials that have contacted
sewage should also be bagged and thrown away. Non-porous materials
with surface mold growth may be saved if they are cleaned well
and kept dry (see step 4).
- Take
Steps to Protect Yourself - the amount of mold particles
in air can increase greatly when mold is disturbed. Consider
using protective equipment when handling or working around
mold contaminated materials. The following equipment can help
minimize exposure to mold:
- Rubber
gloves
- Eye
goggles
- Outer
clothing (long sleeves and long pants) that can be easily
removed in the work area and laundered or discarded
- Medium-efficiency
or high-efficiency filter dust mask (these can be found
at safety equipment suppliers, hardware stores, or some
other large stores that sell home repair supplies) --
at a minimum, use an N-95 or equivalent dust mask
- Take
Steps to Protect Others - plan and perform all work to
minimize the amount of dust generated. The following actions
can help minimize the spread of mold spores:
- Enclose
all moldy materials in plastic (bags or sheets) before
carrying through the home
- Hang
plastic sheeting to separate the work area from the rest
of the home
- Remove
outer layer of work clothing in the work area/wash separately
or bag
- Damp
clean the entire work area to pick up settled contaminants
in dust
- Clean
Surfaces - surface mold growing on non-porous materials such
as hard plastic, concrete, glass, metal, and solid wood can usually
be cleaned. Cleaning must remove and capture the mold contamination,
because dead spores and mold particles still cause health problems
if they are left in place.
- Thoroughly
scrub all contaminated surfaces using a stiff brush, hot water
and a non-ammonia soap/detergent or commercial cleaner
- Collect
excess cleaning liquid with a wet/dry vacuum, mop or sponge
- Rinse
area with clean water and collect excess rinse water
- Disinfect
Surfaces (if desired) -
after cleaning has removed all visible mold and other soiling
from contaminated surfaces, a disinfectant may be used to kill
mold missed by the cleaning. In the case of sewage contamination,
disinfection must be performed. Contact your home inspector for
advice.
- Mix 1/4
to 1/2 cup bleach per gallon of water and apply to surfaces
where mold growth was visible before cleaning. The solution
can be applied with a spray bottle, garden sprayer, it can
be sponged on, or applied by other methods.
- Collect
any run-off of bleach solution with a wet/ dry vacuum, sponge
or mop. However, do not rinse or wipe the bleach solution
off the areas being treated -- allow it to dry on the surface.
Always handle
bleach with caution. Never mix bleach with ammonia -- toxic chlorine
gas may result. Bleach can irritate the eyes, nose, throat, and
skin. Provide fresh air (for example, open a window or door).
Protect skin and eyes from contact with bleach. Test solution
on a small area before treatment, since bleach is very corrosive
and may damage some materials.
- Remain
on Mold Alert
- Continue looking for signs of moisture problems or return of
mold growth. Be particularly alert to moisture in areas of past
growth. If mold returns, repeat cleaning steps and consider using
a stronger solution to disinfect the area again. Regrowth may
signal that the material should be removed or that moisture is
not yet controlled.
When can we rebuild?
Rebuilding and refurnishing must wait until all affected materials
have dried completely. Be patient it takes time to dry out wet
building materials.