Mold, Moisture and Your Home
- The key to mold control is moisture control.
mold is a problem in your home, you should clean up the mold promptly and fix the water problem.
- It is important to dry water-damaged areas and
items within 24 to 48 hours to prevent mold growth.
Why is mold growing in my home?
Molds are part of the
natural environment. Outdoors, molds play a part in nature by breaking down dead organic matter, such as fallen leaves and
dead trees. But indoors, mold growth should be avoided. Molds reproduce by means of tiny spores; the spores are invisible
to the naked eye and float through outdoor and indoor air. Mold may begin growing indoors when mold spores land on surfaces
that are wet. There are many types of mold, and none of them will grow without water or moisture.
Can mold cause health problems?
Molds are usually not
a problem indoors, unless mold spores land on a wet or damp spot and begin growing. Molds have the potential to cause
health problems. Molds produce allergens (substances that can cause allergic reactions), irritants and, in some cases,
potentially toxic substances (mycotoxins). Inhaling or touching mold or mold spores may cause allergic reactions in
sensitive individuals. Allergic responses include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and
skin rash (dermatitis). Allergic reactions to mold are common. They can be immediate or delayed. Molds can
also cause asthma attacks in people with asthma who are allergic to mold. In addition, mold exposure can irritate the
eyes, skin, nose, throat and lungs of both mold-allergic and non-allergic people. Symptoms other than the allergic and
irritant types are not commonly reported as a result of inhaling mold. Research on mold and health effects is ongoing.
This article provides a brief overview; it does not describe all potential health effects related to mold exposure.
For more detailed information, consult a health professional. You may also wish to consult your state or local
How do I get rid of
It is impossible to get rid of all mold and mold
spores indoors. Some mold spores will be found floating through the air and in house dust. Mold spores will not grow
if moisture is not present. Indoor mold growth can and should be prevented or controlled by controlling moisture indoors.
If there is mold growth in your home, you must clean up the mold and fix the water problem. If you clean up the mold but don't
fix the water problem, then, most likely, the mold problem will recur.
Who should do the cleanup?
This depends on a number of
factors. One consideration is the size of the mold problem. If the moldy area is less than about 10 square feet
(less than roughly a 3-foot by 3-foot patch), in most cases, you can handle the job yourself, following the guidelines below.
Tips and Techniques
- If there has been a lot of water damage, and/or mold growth covers
more than 10 square feet, consult with an InterNACHI inspector.
- If you choose to hire a contractor (or other
professional service provider) to do the cleanup, make sure the contractor has experience cleaning up mold. Check references
and ask the contractor to follow the recommendations of the EPA, the guidelines of the American Conference of Governmental
Industrial Hygenists (ACGIH), or other guidelines from professional or government organizations.
- Do not run the HVAC
system if you know or suspect that it is contaminated with mold. This could spread mold throughout the building.
the water and/or mold damage was caused by sewage or other contaminated water, then call in a professional who has experience
cleaning and fixing buildings damaged by contaminated water.
- If you have health concerns, consult a health
professional before starting cleanup.
The tips and techniques presented in this section
will help you clean up your mold problem. Professional cleaners or remediators may use methods not covered here. Please
note that mold may cause staining and cosmetic damage. It may not be possible to clean an item so that its original
appearance is restored.
- Fix plumbing leaks and other water problems as
soon as possible. Dry all items completely.
- Scrub mold off hard surfaces with detergent and water, and dry
- Absorbent or porous materials, such as ceiling tiles and carpet, may have to be thrown away if
they become moldy. Mold can grow on or fill in the empty spaces and crevices of porous materials, so the mold may be difficult
or impossible to remove completely.
- Avoid exposing yourself or others to mold.
- Do not paint or caulk
- Clean up the mold and dry the surfaces before painting. Paint applied over moldy surfaces is likely
to peel. If you are unsure about how to clean an item, or if the item is expensive or of sentimental value, you may
wish to consult a specialist. Specialists in furniture repair and restoration, painting and art restoration and conservation,
carpet and rug cleaning, water damage, and fire or water restoration are commonly listed in phone books. Be sure to ask for
and check references. Look for specialists who are affiliated with professional organizations.
to Wear When Cleaning Moldy Areas:
- Avoid breathing in mold or mold spores. In order to limit your exposure
to airborne mold, you may want to wear an N-95 respirator, available at many hardware stores and from companies that advertise on the Internet. (They cost about $12 to $25.) Some N-95 respirators resemble a paper
dust mask with a nozzle on the front, and others are made primarily of plastic or rubber and have removable cartridges
that trap and prevent most of the mold spores from entering. In order to be effective, the respirator or mask must fit
properly, so carefully follow the instructions supplied with the respirator. Please note that the Occupational Safety and
Health Administration (OSHA) requires that respirators fit properly (via fit testing) when used in an occupational setting.
- Wear gloves. Long gloves that extend to the middle
of the forearm are recommended. When working with water and a mild detergent, ordinary household rubber gloves may be
used. If you are using a disinfectant, a biocide such as chlorine bleach, or a strong cleaning solution, you should
select gloves made from natural rubber, neoprene, nitrile, polyurethane or PVC. Avoid touching mold or moldy items with
your bare hands.
- Wear goggles. Goggles
that do not have ventilation holes are recommended. Avoid getting mold or mold spores in your eyes.
How do I know when the remediation or cleanup is finished?
must have completely fixed the water or moisture problem before the cleanup or remediation can be considered finished, based
on the following guidelines:
- You should have completed the mold removal. Visible mold and moldy odors should not be present. Please
note that mold may cause staining and cosmetic damage.
- You should have revisited the site(s) shortly
after cleanup, and it should show no signs of water damage or mold growth.
- People should have
been able to occupy or re-occupy the area without health complaints or physical symptoms.
- Ultimately, this
is a judgment call; there is no easy answer. If you have concerns or questions, be sure to ask your InterNACHI inspector during
your next scheduled inspection.
Moisture and Mold Prevention and Control Tips
- Moisture control is the key to mold control,
so when water leaks or spills occur indoors, ACT QUICKLY. If wet or damp materials or areas are dried within 24 to 48
hours after a leak or spill happens, in most cases, mold will not grow.
- Clean and repair roof gutters
- Make sure the ground slopes away from the building's foundation so that water does not enter or
collect around the foundation.
- Keep air-conditioning drip pans clean and the drain lines unobstructed
and flowing properly.
- Keep indoor humidity low. If possible, keep indoor humidity below 60% relative humidity (ideally,
between 30% to 50%). Relative humidity can be measured with a moisture or humidity meter, which is a small, inexpensive
instrument (from $10 to $50) that is available at many hardware stores.
- If you see condensation or
moisture collecting on windows, walls or pipes, ACT QUICKLY to dry the wet surface and reduce the moisture/water source. Condensation
can be a sign of high humidity.
Actions that will help to reduce humidity:
- Vent appliances that produce moisture, such as clothes dryers, stoves, and kerosene
heaters, to the outdoors, where possible. (Combustion appliances, such as stoves and kerosene heaters, produce water
vapor and will increase the humidity unless vented to the outside.)
- Use air conditioners and/or
de-humidifiers when needed.
- Run the bathroom fan or open the window when showering. Use exhaust fans or open windows
whenever cooking, running the dishwasher or dishwashing, etc.
Actions that will help prevent condensation:
- Reduce the humidity (see above).
ventilation and air movement by opening doors and/or windows, when practical. Use fans as needed.
cold surfaces, such as cold water pipes, with insulation.
- Increase air temperature.
Testing or Sampling for Mold
Is sampling for mold needed? In most cases, if visible mold
growth is present, sampling is unnecessary. Since no EPA or other federal limits have been set for mold or mold spores,
sampling cannot be used to check a building's compliance with federal mold standards. Surface sampling may be useful
to determine if an area has been adequately cleaned or remediated. Sampling for mold should be conducted by professionals
who have specific experience in designing mold sampling protocols, sampling methods, and interpreting results. Sample
analysis should follow analytical methods recommended by the American Industrial Hygiene Association (AIHA), the American
Conference of Governmental Industrial Hygienists (ACGIH), or other professional organizations.
Suspicion of Hidden Mold
You may suspect hidden
mold if a building smells moldy but you cannot see the source, or if you know there has been water damage and residents are
reporting health problems. Mold may be hidden in places such as the backside of dry wall, wallpaper or paneling, the top-side
of ceiling tiles, or the underside of carpets and pads, etc. Other possible locations of hidden mold include areas inside
walls around pipes (with leaking or condensing pipes), the surface of walls behind furniture (where condensation forms), inside
ductwork, and in roof materials above ceiling tiles (due to roof leaks or insufficient insulation).
Investigating Hidden Mold Problems
Investigating hidden mold problems
may be difficult and will require caution when the investigation involves disturbing potential sites of mold growth. For example,
removal of wallpaper can lead to a massive release of spores if there is mold growing on the underside of the paper. If you
believe that you may have a hidden mold problem, consider hiring an experienced professional.
Cleanup and Biocides
Biocides are substances that can destroy living
organisms. The use of a chemical or biocide that kills organisms such as mold (chlorine bleach, for example) is not recommended
as a routine practice during mold cleanup. There may be instances, however, when professional judgment may indicate its use
(for example, when immune-compromised individuals are present). In most cases, it is not possible or desirable to sterilize
an area; a background level of mold spores will remain, and these spores will not grow if the moisture problem has been resolved.
If you choose to use disinfectants or biocides, always ventilate the area and exhaust the air to the outdoors. Never mix chlorine
bleach with other cleaning solutions or detergents that contain ammonia because toxic fumes could be produced.
Please note: Dead mold may still cause allergic reactions in some
people, so it is not enough to simply kill the mold; it must also be removed.
Ten Things You Should Know
health effects and symptoms associated with mold exposure include allergic reactions, asthma, and other respiratory complaints.
2. There is no practical way to
eliminate all mold and mold spores in the indoor environment; the way to control indoor mold growth is to control moisture.
3. If mold is a problem in your
home, you must clean up the mold and eliminate sources of moisture.
4. Fix the source of the water problem or leak to prevent mold growth.
indoor humidity (to 30% to 60%) to decrease mold growth by:
a. venting bathrooms, dryers, and other moisture-generating sources to the outside;
b. using air conditioners and de-humidifiers;
c. increasing ventilation; and
d. using exhaust fans
whenever cooking, dishwashing, and cleaning.
6. Clean and dry any damp or wet building materials and furnishings within 24 to 48 hours to
prevent mold growth.
7. Clean mold off hard surfaces with water and detergent, and dry completely. Absorbent
materials that are moldy (such as carpeting and ceiling tiles) may need to be replaced.
condensation. Reduce the potential for condensation on cold surfaces (i.e., windows, piping, exterior walls, roof and
floors) by adding insulation.
9. In areas where there is a perpetual moisture problem, do not install carpeting.
Molds can be found almost anywhere; they can grow on virtually any substance, provided moisture is present. There are molds
that can grow on wood, paper, carpet, and foods.