What Is It?
Mold is the common word for any fungus that grows on food or damp building materials. It often looks like a stain and comes in a variety of colors. In nature, mold helps decompose or break-down leaves, wood and other plant debris. Molds become a problem when they go where they are not wanted and digest materials such as our homes. In some cases, however, mold may not be visible but may have a musty odor. If allowed to grow, mold can contribute to poor indoor air quality.
Mold requires three things to grow:
- Food material (can be just about anything – leather, fabric, paint, wood)
Washing, cooking, air humidifiers, unvented clothes dryers, condensation and leaks from the outside all produce the kind of indoor moisture that mold needs to grow. Also, poor ventilation contributes to higher humidity levels and leads to condensation, which also allows mold to grow.
What is the health impact?
In order to reproduce or when disturbed, molds release small “spores” into the air and these spores are small enough that people can actually breathe them in. Our reaction to the spores is what causes illness. Mold has a probable link to a wide variety of symptoms, depending on species type and each individual’s personal reaction. Common symptoms may include:
- Eye, nose and throat irritation
- Coughing and phlegm build-up
- Wheezing and shortness of breath
- Allergic reactions.
Although healthy adults may not react to mold, at special risk are those who already have allergy sensitivities or asthma, lung disease, and also those with weakened immune systems such as the elderly, or with leukemia or AIDS. A small number of molds produce toxins called mycotoxins. When people are exposed to high levels of mold mycotoxins they may suffer toxic effects, including fatigue, nausea, headaches, and irritation to the lungs and eyes. In some cases, most famously with what is popularly called, “toxic black mold,” mycotoxins can lead to fatalities. In addition to the health impact, mold can be very costly for homeowners if not quickly and effectively resolved.
Sources of indoor moisture that may cause mold problems:
- Backed-up sewers
- Leaky roofs
- Damp basement or crawl spaces
- Constant plumbing leaks
- Unseasoned firewood
- Steam from cooking
- Shower/bath steam and leaks
- Wet clothes on indoor drying lines
- Clothes dryers vented indoors
- Combustion appliances not exhausted to the outdoors
- Carpet directly on cement floors may absorb moisture and as a result encourage mold growth
- Stagnant water that has accumulated in ducts, humidifiers, dehumidifiers and air-conditioners
Building Materials that support mold growth
- Gypsum board
- Ceiling tiles
- Wall coverings
- Carpet pads
- Keep homes dry. Control relative humidity levels to less than 60 percent, using dehumidifiers if necessary. Clean humidifiers frequently.
- Repair all leaks promptly.
- If there has been a flood or water damage, take immediate action and remove the water and wet materials. Dry all porous materials and furnishings within 48 hours. If mold grows on any porous materials, such as drywall, ceiling tiles or wood, discard and replace.
- Run bathroom exhaust fans while showering.
- House plants can improve indoor air quality by filtering carbon dioxide; however, if they are over-watered, they can encourage mold growth.
How do I test for it?
We usually only conduct a mold investigation when a client exhibits symptoms, that are associated with allergies or breathing problems or has visually seen or smelled mold.
Ask yourself these questions:
- Do you ever find yourself more tired at home than you did before you left work?
- Do you see more signs of cold or flu symptoms amongst your family?
- Is there any particular area or room that smells musty or “earthy” even though you keep a clean home?
- Do you have high moisture in your home from humidifiers, internally vented clothes dryers, frequent showers, little ventilation or lots of plants?
- Can you see stains or discolorations on floors, walls, window panes, fabrics, carpets and other indoor surfaces?
Mold can also grow unseen behind drywall, wall paper, baseboards, inside of cabinets, and under carpeting. In one case, we found mold growing inside an air conditioning vent inside a gym, which was blowing spores to all gym users inside the conveniently humid environment!
The goal of mold sampling is to help determine whether the particulates present in the indoor environment are elevated enough to negatively affect or cause allergic symptoms with the individuals that occupy the indoor environment. If the individuals are experiencing allergic symptoms, you then have to ask whether or not the symptoms are associated with the elevated particulates in the indoor environment of a specific building or room. If symptoms abate a few hours after leaving a building, it is likely associated with the building and the circumstances call for further investigation, especially if the symptoms are severe or are experienced by many people.
If a problem is found, how can I remediate?
The number one thing that you can do to counter the growth of mold is to prevent or reduce the presence of persistent dampness on interior surfaces in your home. Of the items that mold needs to grow, moisture is the only one that we can really control. Mold is much easier to prevent than to remove!
- Stop water leaks, whether from outside or plumbing. Keep water away from concrete slabs and basement walls.
- Increase ventilation, especially along the inside of exterior walls. Use a fan and dehumidifier to control the relative humidity.
- Make sure that warm air flows into all areas of the home. Move large objects a few inches away from the inside of exterior walls to increase air circulation.
- Install and use exhaust fans in bathrooms, kitchens, and laundry rooms.
- Clean and dry water damaged carpets, clothing, bedding, and upholstered furniture within 24 to 48 hours, or consider removing and replacing damaged furnishings.
- Vacuum (HEPA filter-equipped machine) and clean your home regularly to remove mold spores.
- Check around your windows for signs of condensation and water droplets. Wipe them up right away so mold can’t start to grow
Generally, if mold is only found on a non-porous surface smaller than 10 square feet, you can remove it yourself. Furniture, large porous materials, or items that cannot be washed should be discarded. Note: do not paint over mold, as mold will eat the paint.
Source: Washington State Department of Health
We are frequently asked whether landlords are obligated to remove mold. With a few exceptions, landlord responsibilities regarding mold have not been clearly spelled out in building codes, ordinances, statutes, or regulations. Below is a discussion of the few states and cities that do have mold laws, and an explanation of how landlords can be held responsible for mold problems even absent specific laws governing mold.
Federal Law. No federal law sets permissible exposure limits or building tolerance standards for mold.
State Laws. California, Texas, New Jersey, Indiana, and Maryland have all passed laws aimed at developing guidelines and regulations for mold in indoor air.
For example, California’s “Toxic Mold Protection Act of 2001” authorizes the state’s Department of Health Services (DHS) to set permissible levels of indoor mold exposure for sensitive populations (like children, or people with compromised immune systems or respiratory problems). The California law also allows DHS to develop identification and remediation standards for contractors, owners, and landlords and requires landlords to disclose to current and prospective tenants the presence of any known or suspected mold. To date, the DHS has not published its findings.
Similar laws are sure to develop in other states.
Local Laws. A few cities have enacted ordinances related to mold. For example:
- New York City. Landlords in New York City must follow Department of Health guidelines for indoor air quality.
- San Francisco. In San Francisco, mold is considered a legal nuisance, putting it into the same category as trash accumulation or an infestation of vermin. Tenants (and local health inspectors) can sue landlords under private and public nuisance laws if they fail to clean up serious problems.
The Landlord’s Duty to Maintain Habitable Premises
Even if your state or city doesn’t have specific mold laws, your landlord may still be liable for a mold problem in your rental.
Mold caused by a landlord’s failure to fix leaks. Landlords in all states but Colorado and Arkansas are responsible for maintaining and repairing rental property, and this extends to fixing leaking pipes, windows, and roofs — the causes of most mold. If the landlord doesn’t take care of leaks and mold grows as a result, you may be able to hold the landlord responsible if you can convince a judge or jury that the mold has caused a health problem. (To learn more about the landlord’s duty to repair, read Nolo’s article Renter’s Rights to Privacy and Repairs FAQ.)
Mold caused by tenant behavior. The liability picture changes when mold grows as the result of your own behavior, such as keeping the apartment tightly shut, creating high humidity, or failing to maintain necessary cleanliness. When a tenant’s own negligence is the sole cause of injury, the landlord is not liable.
Most of our clients have had some success in getting landlords to take action. The danger, is that many landlords, even well-meaning, worsen the problem by using incorrect clean-up techniques such as:
- Scrubbing mold, releasing spores everywhere
- Not sealing the contaminated area, leading to spores entering the HVAC system and circulating through the residence
- Not providing clean-up workers eye or breathing protection
- Painting over the mold, which provides mold with even more material to grow
For porous materials or a large area, our typical recommended approach is to use a disinfectant that is fast-acting, effective against the mold identified, is cost-effective, and perhaps most importantly, does not leave chemical residues (leaves a salt residue only). We have also recommended the prevention of mold reoccurrence with the application of special coatings.
We recommend you contact us in the following situations:
- Family member(s) are exhibiting allergic reactions in your home but not elsewhere
- Have recently had water damage and would like to prevent mold growth
- Can smell mold odor but cannot locate
- Have located mold but do not want to remediate yourself
- Have identified mold but do not trust landlord to remediate