Mold: Is your home at risk?

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February 2006

Mold: Is your home at risk?

A bigger problem for your house than your health

http://www.consumerreports.org/cro/home-garden/home-improvement/mold-

is-your-home-at-risk-206/overview/

Mold is everywhere, even in the courtroom. Since the late 1990s,

mold claims have surged, with more than 10,000 mold-related lawsuits

happening at one time, according to the Insurance Information

Institute, an information and analysis organization. In November, a

California family was awarded $22.6 million in the settlement of a

toxic-mold case.

Of the roughly 1,000 strains of household mold, Stachybotrys

chartarum-- also popularly called black or toxic mold--has generated

the most headlines. Some studies have linked it to a form of

pulmonary hemorrhage in infants; others have been inconclusive. But

despite the flood of news reports, most people needn't be overly

concerned about the effects of mold on their health.

Small, isolated patches of mold growing on and around your shower

curtain or bathtub usually aren't a problem. But mold that covers a

large area can aggravate asthma and other respiratory conditions.

Mold can grow out of control wherever buildings retain too much

moisture for too long without drying out, even in arid climates.

Many types can cause stuffed or runny noses, rashes, and itchy eyes

if you're allergic to mold. They may also pose more-serious risks to

people with undeveloped or impaired immune systems, including

infants, children, seniors, and those with HIV or cancer.

The bottom line: Excessive mold typically means that water intrusion

or high indoor humidity is causing a potentially serious moisture

problem. Mold can damage your home by weakening floors, walls, and

ceilings as it feasts on decaying wood and wallboard, ceiling tiles,

caulk, cellulose insulation, and other organic materials. Toxic or

not, it isn't good for you or your home.

As Consumer Reports addressed in our September 2005 flood insurance

report, insurers aren't making the financial burden of mold any

easier. Because of huge jury verdicts and millions of claims,

insurance companies have sharply reduced or eliminated coverage for

mold remediation in some states. Even if your home is covered for

mold damage, you need to know how to spot mold contamination and the

basics of cleanup to help you get the most-effective remediation

possible. For extensive jobs, you also need to know how to find a

qualified professional. Here are some tips to help you locate and

eliminate mold, and how to prevent it from coming back.

HOW MUCH IS TOO MUCH, AND WHERE TO LOOK

Small surface patches of mold on bath tiles usually aren't a

problem, since the mold probably hasn't reached the wallboard

beneath. But soaked wood, wallboard, ceiling tiles, and other

organic materials quickly give airborne mold spores a moist and

hospitable environment that allows colonies to spread on walls, in

corners, around air ducts, and near pipes.

Suppose you don't see any mold, but smell a musty odor or are

experiencing a chronic runny nose, sore throat, or other symptoms.

You'll have to do some sleuthing:

Finding mold you can't see. If your home has been flooded, check for

mold inside heating, ventilation, and air-conditioning ducts before

turning on the systems again. Otherwise, mold contamination could be

spread throughout your home.

Check for any signs of mold beneath carpets and around windows. Also

remove cover plates for cable-TV connections, phones, and Internet

connections, and use a flashlight to peer behind walls and wallpaper

for signs of mold there.

Once you've found the source of moisture and mold, use plastic

sheeting to contain and prevent mold spores from spreading

throughout the house. If the mold covers less than 10 square feet,

you may be able to eliminate the problem yourself. But you'll need

to hire a professional mold remediator (see Finding a pro) for

larger areas if you or a family member is highly allergic, or if

contaminated water is involved. You'll also need a pro if your

ventilation system is contaminated (see Ducts: A Special Concern in

our mold report).

Avoid mold test kits. Based on our tests of four kits available at

home centers and online, we don't recommend them. We found major

flaws with each kit. First, none of the kits have expiration dates.

That's problematic for kits that use petri dishes and growth media

because old media could affect the reliability and accuracy of the

test results. One of the kits was difficult to open and could become

contaminated as you wrestled with the packaging. Others were simply

a pain to use. Finally, three kits we tested made claims about

detecting toxic mold, though none of their lab analyses are specific

enough to tell you if you actually have any. To learn the specific

problems of each kit, see mold test kits.

Eliminate the source

Repair leaky roofs, poor or missing chimney and window flashing,

missing or damaged shingles or siding, and leaky pipes.

Repair or replace damaged gutters and leaders.

For mold caused by exterior flooding, evaluate the foundation and

grading of your home to make sure that land is sloped away from the

foundation of your house. (See our report on disaster defenses for

your home.)

Remove the mold

Begin by protecting yourself with an N-95 disposable respirator

approved by the National Institute of Occupational Safety and

Health; goggles; and heavy-duty rubber, neoprene, or PVC gloves.

Packages of N-95 respirators cost about $12 to $25 and are available

in hardware and building-supply stores, by mail, and online. Make

sure the respirator is fitted properly. (See our mold report for

instructions.)

Bag and discard any carpet, ceiling tiles, wallboard, paper,

insulation, or other porous materials that have been wet for 48

hours or more. They promote mold growth even if they aren't visibly

contaminated.

Scrub other materials with a strong solution of detergent and water

or 1 cup of chlorine bleach per 5 gallons of water. Wear plastic or

rubber gloves and eye protection. Warning: Never mix bleach with any

other cleaning solution, especially ammonia, which creates a

poisonous gas. Avoid biocides other than chlorine bleach, which can

trigger allergic reactions. These biocides usually aren't

recommended for home use by nonprofessionals, and they are federally

regulated for specific uses when applied by professionals.

Wood studs and exposed joists may have to be wire-scrubbed with

bleach, sanded, and dried out before reinstalling wallboard and

flooring.

Keep mold from coming back.

Allow all surfaces to thoroughly air-dry.

Vacuum up debris and particles using a wet-dry shop vac with a HEPA

filter.

Decontaminate clothing by washing it in hot water with detergent.

Bag in plastic and discard all used masks and dirty materials.

Install outside-venting exhaust fans in bathrooms and dehumidifiers

in basements to keep relative indoor humidity levels between 30 and

50 percent. You can measure relative humidity using a hygrometer

(about $10 to $50 at hardware stores).

Don't use wallpaper or carpets in bathrooms and other damp areas.

Leave flood-prone basements unfinished, since finished basements can

be more susceptible to mold problems, according to the 2004 Damp

Indoor Environments study conducted by the National Academy of

Sciences Institute of Medicine.

Don't bother with mold test kits. In theory, these kits should be

able to confirm that you or the remediator has truly cleaned up the

mold. Unfortunately, our tests of four common kits found they can't

be relied on. When we sent six unused petri dishes back to the

companies for testing--like you might after cleaning up mold--three

of the reports came back saying we did have mold, suggesting they

might have been unintentionally contaminated at some point. To learn

about the other problems we found, see mold test kits.

For more information, see our full report on cleaning up mold. Other

helpful information sources include the U.S. Environmental

Protection Agency mold fact sheet (www.epa.gov/mold/index.htm) and

the national Centers for Disease Control and Prevention mold

prevention and remediation materials

(www.bt.cdc.gov/disasters/mold/protect.asp) and

www.cdc.gov/mold/strats_fungal_growth.htm.

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