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Moulds in the house: to find them, to eliminate them and to prevent their re-appearance

Moulds in the house: to find them, to eliminate them and to prevent their re-appearance

Any form of mould which grows in your house or your dwelling can pose a serious health risk, particularly if a member of your family suffers from asthma or allergies. If however, you know where to look at and know what it resembles, and know how to prevent its apparition or how to eliminate it, you should be able to control any possible problem of moulds, and to keep the members of your family in health and safety.

What makes a mould grow?

The mould has a microscopic mushroom shape which has the capacity to grow and to reproduce itself quickly. The mould is an integral part of our environment, because, in addition to breaking up waste, some produce even antibiotics.

The situation becomes problematic when the mould proliferates where it is not welcome as in your house. Once inside your house, the mould can generate problems which go from damage to materials to allergic reactions and respiratory diseases. The mould is not, however, a problem in the case of structural damage and of rot of wood because, technically, these phenomena result from other types of mushrooms.

What can you do to prevent the moulds from settling on your premise?

Stage 1: Determine if you have a mould problem.

The mould tends to grow everywhere where there is an excess of moisture. That includes the kitchens and the bathrooms where one finds plumbing leaks, the wet or cold basements, wet windowsills and everywhere where water penetrates through the floor, the walls or the ceiling. One will not find mould in the kitchens and the bathrooms, unless those are dealing with clogged water leakages or other problems linked to moisture.

In order for the mould to proliferate, it is not necessary to be in the presence of running water. A wet environment can provide sufficient moisture to ensure the growth of mould. Activities, like the baths, the laundry, cooking, the interior plants in too large numbers, pets, etc…constitute sources of moisture. In addition, in cold weather, moisture can settle on cold surfaces, like the glazings or the walls that lack insulation.

Discolouration and spots are visible signs of the presence of mould. If you suspect that a spot is in fact mould, apply a drop of bleaching agent on it. It can then be a question of mould if the spot changes colour. Moreover, a persistent odour of mildew is indicative of the presence of mould.

Even if you do not see mould or if there is no odour, the presence of wet or humid zones or signs of water leakage should indicate to you that you are in the presence of mould or that it will not be long in appearing. When people suspect that they have a problem of mould, the first thing which comes to them to mind is to have the house examined to determine if it comprises moulds. These tests will not be useful, save your money then and use it to eliminate the problem and the work carried out by a specialist.

It is also important to remember that the mould is only one of the irritating substances which can cause an allergic reaction or respiratory difficulties. Many other elements, like the cigarette, the storage inside of toxic chemical substances or of powerful cleaning products, the use of a heating device or a non-ventilated hearth, candles or incense, even the air purifiers can be irritating for certain people.

If a member of your family has difficulty breathing, look then for other possible causes.

Stage 2: Eliminate the problem

If your house presents only one small zone of mould (not more approximately than a square meter), you can clean it yourself using a simple solution of water and non-scented detergent, rubber gloves and a respiratory mask to protect you.

If the zone of mould covers a surface of between one and three square meters (let us say the size of a plywood sheet of 4 x 8 sq f), you could perhaps clean it yourself, although in such a case, you will have to carry a more robust respiratory mask of protection and the working area may require a particular treatment. It is initially advisable to consult a specialist to discover how the mould came there. Communicate with the office of your area of the Canadian Mortgage and Housing Corporation (CMHC) to obtain a list of qualified investigators of the quality of the interior air.

Stage 3: To prevent the mould from appearing

Obviously, the best way of getting rid of a problem of mould is not to let the mould appear in your house.

Initially, find and clog the escapes which let water infiltrate from the outside into the house. Clean and regularly replace the filter of the heating appliance. Keep your house clean and frequently use the vacuum cleaner, preferably using a central vacuum cleaner which evacuates the air to the outside, or of a vacuum cleaner equipped with a HEPA filter.

Keep your house well-arranged, because not only does the mould proliferate on the materials which absorb and retain moisture, but the disorder also reduces the air circulation. Moreover, see to it that all the parts of your house are heated. Think of other ways of maintaining your house dry. Extend the linen to be dried outside when the weather allows it, and not inside. Make the ventilators of kitchen and bathroom function. From spring to autumn, the use of a dehumidifier to control moisture in the basement is impossible to circumvent in the majority of the regions of Canada. In winter, if you see condensation on the windows, that indicates that the water content is perhaps too high.

In the case of the apartments or of the houses for rent

In the case of people who live in a rented house or an apartment, the responsibility for elimination of the mould falls on the tenant or on the owner, or on both.

To cleanse the air!

By holding you to some of these simple steps, you should be able to keep your house free of mould, and the members of your family healthy and safe, all year long.

For more information on the identification and the treatment of moulds in a house, consult the Website of the CMHC at and launch a research with the key word “mould” or compose 1-800-668-2642.

Source: Dr. Virginia Salares, principal CMHC researcher

About the author

Québec Landlords Association (1)

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