Mold is pervasive in our environment; it occurs indoors and outdoors. In nature, various molds work to decay leaves and trees, returning essential nutrients back into the soil. Mold has also served humankind through some very inventive applications. Experiments in the 1920s revealed that a species of mold, called Penicillium, when added to a sweet solution, released a chemical as part of its metabolic processes. That chemical became known as penicillin, a live-saving antibiotic. Molds also have a long history of use in cooking: they are essential to production of some cheeses such as blue cheese. Airborne molds and yeasts provide the leavening agent and distinctive flavour of sourdough bread. Inside our homes, however, mold can cause serious health problems and damage building structures.

Molds are microscopic fungi, a group of organisms that include mushrooms and yeasts. These organisms grow rapidly in the proper conditions and spread quickly through the release of spores into the air. Over 270 different types of molds have been identified in Canadian homes according to the Canadian Mortgage and Housing Corporation (CMHC).

Health Concerns

Molds produce allergens, irritants, and in some cases, potentially toxic substances known as mycotoxins. Inhaling spores or touching mold may cause allergic reactions such as sneezing, runny nose, red eyes, asthma attacks in sensitive individuals, and skin rash.

Exposure to mold can be more severe for infants and children, elderly people, pregnant women, individuals with allergies or respiratory conditions such as asthma, and people with weakened immune systems. Long-term exposure to indoor molds can eventually become dangerous for anyone.

Mold in Our Homes

Our homes can present the ideal habitat for molds to thrive. High indoor humidity (over 70%) is the main culprit in the overgrowth of mold. The following are a few noticeable signs of excess moisture in your home:

• Condensation on the inside of windowpanes
• A musty smell
• Discoloration on furniture *
• Rust on water pipes

Reducing Moisture

If you find your home has a moisture problem, it is essential to your health and the quality of your home to correct the problem as soon as possible. Because mold can spread rapidly, small problems should be taken care of before they become serious. Mold can discolour carpets, walls, furniture and curtains. Eventually, a mold problem left unchecked can lead to wood rot and structural damage. The following are recommended methods of reducing moisture:

• Indoor water leaks or spills should be completely dry within 24 hours to prevent the growth of molds. Open windows and use fans if necessary.
• Vent appliances that produce moisture, such as dishwashers, clothes dryers, stoves, and kerosene heaters to the outside where possible. (Combustion appliances such as stoves and kerosene heaters produce water vapor and will increase the humidity unless vented to the outside.)
• Run the bathroom fan or open the window when showering. Use exhaust fans or open windows whenever cooking, running the dishwasher or dishwashing, etc.
• Increase ventilation or air movement by opening doors and/or windows, when practical. Use fans as needed.
• Use de-humidifiers when needed.
• Insulate cold water pipes where condensation is likely to occur.
• Consult a professional if you suspect you have rainwater penetration in your home. Any such problems should be corrected immediately.

Removing Mold

It is possible to correct small mold problems by removing the existing mold and implementing some of the previously mentioned methods to reduce moisture. CMHC recommends the following procedure for removing mold.

You can clean small areas on your own. A small area is defined as a maximum of three patches each less than a square metre in size. Clean using a detergent solution, safety goggles, household rubber gloves and a disposable dust mask (3M 8210 or equivalent) for protection. You may also use a few drops of bleach in a litre of water however, never mix bleach and detergent.

If mold is present on more than three square metres of your home's interior, assessment by a professional is recommended. The process of cleaning may result in a significant amount of airborne spores; a dust mask may not provide adequate protection. Consider consulting a professional to determine why the mold is there in the first place and correct it.

Considering how quickly mold organisms can reproduce, rapid action is the best approach. Correcting the problem will ensure you have a healthy and sound home for years to come.