Renovation Health Check: Mold and Air Quality

Mold can be a real problem in basements so it’s important to stop it before it starts. In any renovation project, and particularly basement, kitchen and bathroom renovations, you need to take the necessary steps to protect you and your family by using products that will maintain the safety and high air quality of your home.

What is Mold?

Mold is any fungus that grows on food or damp building materials. It grows easily because it only requires air, water, a food source like dust, paint or fabric, and for the temperature to be between 41 to 104 degrees. In a home these elements come together frequently, so mold has the potential to flourish. If mold growth continues untreated it can contribute to poor indoor air quality and cause a number of serious health problems.

How Do I Know If My Home Has Mold?

Mold can appear in a number of different places in a home, but most often you’ll see it in kitchens, baths, and basements (or anywhere that’s had a leak). You’ll be able to recognize it by the color (usually black, green or brown), and the fact that it looks like a stain on the material. In some cases you can’t even see mold, but you’ll know it’s there by the musty odor it gives off.

How to Prevent Mold Growth

The best way to prevent mold growth before it starts is to use a combination of building products that help protect against it. Anytime you’re renovating keep the following things in mind.


Insulation is your first line of defence in preventing mold. ROCKWOOL insulation does not absorb or hold water and will not promote mold or fungi growth. After exposure to water and moisture, it won’t slump in the wall cavity and the R-value will not be affected. In the event it becomes damp or wet the insulation, when thoroughly dried, will maintain the original performance characteristics. ROCKWOOL products are inorganic which provide no food source for mold to grow.


Using the right drywall products, such as moisture and mold resistant wallboard, can help protect your home. They feature a unique technology that combines moisture and mold resistance for walls and is specially engineered to provide enhanced protection against mold growth. Look for these products at your local home improvement store.

Vapor Barrier 

A vapor barrier is designed to keep the moisture in your home from getting inside your walls. Typically, a vapor barrier/retarder is installed on the warm side of the wall, over the insulation and studs.


DryBarrier subfloor system is mold and mildew resistant. It’s ideal for helping to keep
basements dry because where there is concrete, there is moisture, and that can cause mold to develop when it comes in direct contact with flooring. DryBarrier provides a moisture barrier to protect and add warmth to finished floors on concrete slabs.

Kerdi Board
Remember that tile is not waterproof, so it’s important to use a waterproofing system behind the shower walls. Also be vigilant about making sure tubs and sinks are tightly sealed so the water doesn’t leak into the walls.


Make sure that the area is well-ventilated. Make sure your clothes dryer, stove, kitchen and bathroom fans all vent to the outdoors.

More Ways to Prevent and Control Mold Growth

  • Keep the humidity low – about 50% in summer and 30% in winter.
  • Regularly clean and maintain anything that holds water such as air conditioners, humidifiers and dehumidifiers.
  • Use fans in the kitchen when cooking and in the bathroom when showering, and leave them running for a few minutes after you’re done. Make sure the CFM number is appropriate to the size of the room.
  • Make it a habit to regularly check your home for leaks or damp spots. Fix anything you find immediately.
  • Don’t allow mold to grow on indoor plants. The moist soil is the perfect breeding ground for mold and it often goes unnoticed.
  • Don’t leave wet clothes or towels lying around. After you’ve washed them dry them right away.
  • Avoid storing materials such as books, clothes and cardboard boxes in areas of your home that tend to have high humidity. These are breeding grounds for mold.

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