After the Flood: Understanding Mold

Transcription

1 Manitoba Emergency Management Organization Information compiled by Manitoba Energy & Mines After the Flood: Understanding Mold Mold is a common problem for many Manitoba homeowners. If left unchecked, it can damage a home and sometimes creates a significant health risk. Homes which have been flooded are more prone to develop mold. This fact sheet explains what mold is, why it is a concern, and how to determine whether you have a mold problem in your home. What is mold? - Molds (also called mildew or fungi) are micro-organisms. They are found almost everywhere, both indoors and outdoors. They do not require light to grow and thrive in damp or wet conditions. Mold also needs a food source. Many common building materials, finishes and possessions in your home such as wood, drywall, carpeting, bedding, cardboard boxes etc. can support mold growth. Mold can even feed on dust or dirt found on the surface of hard, inorganic materials such concrete, glass, plastic or metal. What do molds look like? - Molds are not always easy to recognize. They often look like "fuzz" or appear to be a stain, smudge or discoloration. The most common molds are black, green or white. However, they can be many other colors ranging from grey to orange to brown. How do molds spread? - Most molds spread by releasing spores. These tiny "seeds" are lightweight allowing them to travel through the air. If they are deposited on a surface that has the right combination of dampness, food and temperature, a new colony of mold can quickly grow. It is common to find mold spores in homes regardless of whether they have been flooded. Should I be concerned about mold in my home? - Yes, especially if your home was flooded. Airborne mold spores and debris from dead mold colonies can cause allergic reactions, asthma episodes and other respiratory problems for some people. Molds can also release complex chemicals into the air that cause serious health problems. However, most people will not develop a health problem if exposed to mold.

2 Mold can also damage your home. A minor mold problem may only mar the appearance of your home. However, if left unchecked, mold can spread and seriously affect the durability or even value of your home. Who is at greater risk when exposed to mold? - It is a wise precaution for everyone to minimize their exposure to mold. However, the following individuals appear to be at higher risk for adverse health effects of mold: infants and children the elderly pregnant women individuals with existing respiratory conditions or sensitivities (e.g. asthma, allergies, etc.) people with compromised immune systems (e.g. patients who are receiving cancer chemotherapy or have had an organ transplant; persons with HIV infection, liver disease, etc.) Don't confuse mold with "efflorescence" - Some concrete basements develop a condition known as "efflorescence." This occurs when water leaches the minerals or salt in the concrete and deposits them on the surface as a white, powdery residue. Efflorescence does not affect the strength or durability of the concrete - it only mars the appearance. Homes in the flood zone may have more efflorescence than usual, even if they never had water in the basement. This is because the moisture levels in the soil surrounding foundations are only slowly returning to normal. It can be difficult to distinguish between efflorescence and mold. In some cases, the dampness that leads to efflorescence will encourage mold and both can "grow" in the same location. For this reason, be cautious and treat areas with efflorescence in the same manner as mold. Should I test my home for mold? - The air and surfaces in your home can be sampled for molds. However, testing is not recommended as the first step to determine if you have a mold problem. There are thousands of varieties of molds and identifying them is a difficult and expensive task, even for experts. Your efforts and money are better directed to simply get rid of any mold and then eliminate the conditions that cause it. Where to check for problems - Inspect your home both for mold and condensation or dampness that can lead to mold. You may discover pre-existing problems. In some cases, these mold or moisture problems may be worse because your home was flooded. Winter is the best time for this inspection, although basements and crawlspaces should also be inspected in the summer. Thoroughly check your entire home - the dampness from basement flooding can create or worsen an existing mold problem upstairs. Here are some key things to check for:

3 Attic and Ceiling frost or dampness on the underside of the roof moldy or wet insulation (may indicate roof leaks or excessive air leakage from the living space into the attic) sagging or stained ceilings (especially around exhaust fans and recessed lights) Walls, Windows and Doors peeling paint, deteriorating siding or efflorescence on brickwork (may be a sign of wetness within the wall) condensation or frost on windows wall damage or wet carpet and underlay below windows frost on door sills Interior mold in the corner of outside walls mold where outside walls meet the ceiling inside closets, especially on outside walls in the bathroom or under the kitchen sink or dishwasher behind furniture, boxes and other stored items Basements and Crawlspaces in an open sump pit in ductwork inside the furnace humidifier between floor joist ends (remove insulation batts not covered with an air-vapour barrier) on damp basement walls, especially corners around leaks from plumbing near water puddles on the basement floor on damp earth or sand in the crawlspace Note: A musty or earthy smell means that mold is probably growing somewhere - maybe unseen. To determine whether mold is growing, gain access to normally hidden or enclosed spaces (i.e. lift carpeting and underlay, cut inspection holes into wall cavities, etc.). How do I get rid of mold? - Quickly destroy any mold you find to prevent it from spreading. Follow this three step process: Step 1 - Disinfect and clean surfaces: Kill mold by wetting it for 15 minutes with unscented household bleach. Next, clean away any dirt or debris on nearby areas using one part bleach in four parts water, plus a small amount of non-ammonia detergent. Finally, rinse the entire area with clean water. (Remember than both

4 visible and hidden surfaces, such as inside walls, may need to be disinfected and cleaned.) Step 2 - Dry surfaces quickly: After disinfecting and cleaning, dry the affected area as soon as possible using fans, dehumidifiers or natural ventilation. A moisture meter is recommended to determine if materials are dry enough to be covered, enclosed or refinished. For information on obtaining a moisture meter, contact the Flood Recovery Information Office in either St. Adolphe, Rosenort or Letellier. Step 3 - Take preventative measures: Most mold problems result from excess moisture. Unless you deal with the moisture problem, mold may continue to reappear. For more detailed advice, read CMHC's "Clean-up Procedures for Mold in Houses." Free copies are available from the Manitoba Emergency Management Organization (MEMO). In Winnipeg, call or visit the Flood Recovery Information Office in St. Adolphe, Rosenort or Letellier. Special precautions Consider these precautions before you begin work to rid your home of mold: Relocate vulnerable individuals - If your home has a mold problem, and if you have a family member who is at an increased risk of health effects from mold, consult your family health care provider. It may be desirable to temporarily relocate these persons until the mold problem is solved. Use appropriate respiratory protection - For small patches of mold (up to about 0.2 square metres - two square feet), use an approved disposable dust mask. The mask or its package should state that it is "NIOSH-approved (TC-21C) for dusts and mists." For larger areas (up to about one square metre -10 square feet), use a full or half-faced respirator with a "NIOSH-approved HEPA filter." These respiratory protection devices are available from safety supply stores and some building supply retailers. Areas with extensive mold growth (larger than one square metre - 10 square feet), are better left to qualified professionals. Protect your skin and eyes - For small areas, use rubber gloves and safety glasses or goggles. For larger areas, also use disposable coveralls and be sure to cover your hair. After you finish working or before you take a meal break, thoroughly wash your hands and any exposed skin. Ventilate the work area - Bleach is a harsh chemical. Ventilate the work area well and never mix bleach with ammonia - the fumes are toxic! Isolate the work area to prevent fumes, dust or mold debris from creating a problem elsewhere in your home. Vacuum with care - Vacuum cleaners can be helpful to remove mold and dirt that can support mold growth. However, ordinary household or shop vacuum cleaners do not trap fine particles and can increase mold exposure. A better alternative is to use either a central vacuum that exhausts directly to the outdoors or a vacuum equipped with a high efficiency "HEPA" filter.

5 Properly dispose of contaminated materials - Any material contaminated with mold, and especially porous materials such as drywall, ceiling tiles, insulation and carpet, must be double-bagged in heavy-duty plastic bags and disposed of properly. This fact sheet is only an introduction to mold problems in a flooded home. Contact MEMO for further information on controlling mold and moisture problems. Further reading - There are many things other than mold that can cause an indoor air quality problem in your home. CMHC's booklet "The Clean Air Guide" contains a stepby-step description on how to create and maintain a healthy indoor environment. Contact MEMO for a copy. Need more advice? - If you feel that your home has a serious mold problem as a result of being flooded, or you need advice on eligible repair expenses, please contact MEMO in Winnipeg at or Many of the measures that solve moisture and mold problems also save energy and help to pay for themselves. If you need impartial, technical advice about what you can do to improve your home, call Manitoba Energy and Mines in Winnipeg at or