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Mold Inspection and Testing

Canadian winters are a prime season for indoor mold growth

A lot of Canadians assume that winter is the down season for mold growth; however, in reality, that couldn’t be any further from the truth. In fact, Canadian winters present plenty of opportunities for mold widespread indoor mold growth.

In warmer parts of the world, mold growth predominately occurs during the summer, when the weather is hot and humid. In Canada, the winters are quite cold, but it’s the primary mold season for the country. Since windows are closed and people spend a lot of time indoors, household mold can increase and with it, create indoor air quality problems.

Understanding the cause of mold growth in winter and the solutions is something that can make a major difference in your health.

Health Canada classified indoor mold growth as a significant health hazard. People who live in homes with damp conditions where mold can grow are likely to develop health problems, including:

  • Eye, nose, and throat irritation
  • Coughing and phlegm buildup
  • Wheezing and shortness of breath
  • Exacerbated asthma symptoms

The difference in temperature between indoor and outdoor spaces is the primary reason why winter is the height of indoor mold growth in Canada. The wider the temperature difference, the more mold can develop. This is caused by a peculiar trait of air. The cooler air is, the less moisture it holds. Therefore, whenever warm indoor air makes its way into colder areas, such as around windows and in wall cavities, in attics, and in basements, the ability for air to retain moisture decreases.

Indoor air with a relative humidity of about 50 percent at 22 degrees C will rise to 100 percent relative humidity when that same air cools to just 11 degrees C, with everything else remaining equal.

Any additional cooling will lead to the formation of water droplets on surfaces.

Mold only grows when there is a sufficient amount of moisture. As soon as moisture develops, mold can flourish. It is because of the dynamic cooling and condensing that windows can get wet on the inside during cold weather, and why mold grows inside wall cavities that lack an effective vapor barrier.

Poorly insulated walls can develop mold on their interior surfaces, too, when the weather gets cold outside and furniture stops warm air from circulating in those locations. If mold grows in your walls in the winter, it’s almost always behind a piece of furniture.

To prevent mold from growing in your house over the winder, you can do two things. Firstly, lower the indoor humidity levels. Secondly, prevent warm indoor air from reaching places where it can cool down and condense, so make sure that walls, roofs, and attics are well insulated.

Mold Inspection & Testing Toronto has years of experience performing mold assessments in homes throughout Toronto and all of Ontario. If you suspect that mold is growing inside your home, we urge you to schedule an appointment for mold testing with a reputable company. To speak with an MI&T representative, call 855.600.6653.