Mold Questions and Answers

Mildew is a common name for certain molds that grow flat on damp surfaces, often as a powdery white or grey film on shower grout or window sills. Both are fungi and both need moisture. Mildew usually stays on the surface and wipes off, while mold that has worked into porous material such as drywall or wood often has to be cut out. Either way, the fix starts with the moisture.

Yes. Not every mold gives off a strong odor, and growth sealed inside a wall cavity or under flooring may not be noticeable in the room. A lack of smell does not rule mold out. Water staining, peeling paint, warped trim, a past leak, or indoor humidity that stays above 60 percent are better reasons to look closer.

Yes. Indoor mold depends on moisture, not the season. In winter, warm, humid indoor air condenses on cold surfaces such as window glass, exterior walls, closet corners on outside walls, and the underside of attic roof sheathing. Those surfaces can stay wet for weeks, which is enough for growth.

It can. Condensation that runs down the glass every morning keeps sills, trim, and the drywall below them damp, and those are common places for mold to start. Running bathroom and kitchen exhaust fans, keeping indoor humidity between 30 and 50 percent as EPA recommends, and wiping sills dry all help.

Not in a useful way. Most store kits are open dishes that catch spores from the air, and mold spores are present in almost all indoor and outdoor air, so the dish nearly always grows something. That result does not tell you how much mold there is, where it is coming from, or whether it is a problem. When mold is visible, EPA notes that sampling is usually unnecessary; the priority is removing it and fixing the moisture.

Not on their own. A HEPA air purifier can capture spores that are floating in the air and lower their concentration in a room, which some people with allergies find helpful. It does nothing to growth that is still active on a wall, ceiling, or under a floor, and that growth keeps releasing spores. Removing the growth and correcting the moisture is what solves it.

Plastic sheeting seals off the work area, and a HEPA air scrubber exhausts filtered air out of that space. Because air is being pulled out, the pressure inside the containment drops slightly below the rest of the building, so air leaks in rather than out. That keeps spores and dust disturbed during removal from drifting into clean rooms.

Clearance is the check done before containment comes down. It starts with a visual inspection and moisture readings to confirm materials are clean and dry. Air samples may also be taken and compared with an outdoor sample. Some property owners hire an independent third party for this step so the company that did the work is not grading its own job.

ANSI/IICRC S520 is the Standard for Professional Mold Remediation, published by the Institute of Inspection, Cleaning and Restoration Certification. It sets out procedures for assessing mold damage, containing the work area, removing contamination, and verifying the result, with an emphasis on physically removing growth rather than covering or spraying it.

Clear a path from the door to the work area, move vehicles or outdoor items that block access, and let us know where the water shut-off and HVAC controls are. Keep children, pets, and anyone with asthma or a weakened immune system away from the area. Do not try to scrub, tear out, or bag moldy material yourself beforehand, because disturbing it spreads spores into the rest of the house.

Ask for a written scope showing the affected area and square footage, before and after photographs, moisture readings, a description of what was removed and how, the moisture source that was identified with what was recommended to correct it, and the clearance results. Keep it. Insurers, buyers, home inspectors, and a future disclosure form may all ask for it.

It depends on the material. Hard, non-porous items such as glass, metal, and sealed plastic can usually be cleaned. Washable clothing often cleans up with a normal wash. Porous items with visible growth, such as mattresses, upholstered furniture, carpet, paper, and books, are often not worth saving, and EPA notes they may need to be thrown away. Items with sentimental or monetary value can sometimes be professionally restored.

Pets can react to mold much like people do, with sneezing, coughing, itchy skin, or breathing irritation, and pets that spend time close to the floor or in damp basements may be more exposed. Keep pets out of the work area during remediation, and talk to your veterinarian if you notice symptoms.

Renters insurance generally covers a tenant's own belongings, not the building. Damage to belongings may be covered when mold follows a sudden, accidental water event that the policy covers, and is often excluded when it comes from long-term humidity or a slow leak. Repairs to the structure itself are usually the landlord's responsibility. Check the exclusions in your own policy.

It can be, when the moisture source was corrected and the work was documented. Ask the seller for the scope, photographs, moisture readings, clearance results, and what was done about the cause, and have your own inspector look at that area. A past remediation with good records is usually less of a concern than an old leak nobody investigated.

Get the extent and the source assessed before your inspection deadline passes, and ask the seller for any records of past water damage or repairs. Then talk with your agent about the options your agreement of sale allows, such as a repair, a credit, or renegotiating. Pennsylvania's Seller Disclosure Law requires sellers to disclose known material defects. This is general information, not legal advice.