Mold-proofing your home, room by room

Molds growing inside the home are a concern for many people;  they can damage or discolour materials and fabrics, they are an indicator or worse things to come (ie. wood rot and structural damage due to high levels of moisture), they cause a stale and earthy odour, and they can even disintegrate paper and cardboard.  Perhaps, though,  the largest concern for most (and understandably the most important) is that when growing inside your home they can cause a range of health issues and concerns as they release chemicals and spores into the air; especially at risk in this case are pregnant women, infants and the elderly where certain health problems (ie. respiratory disease or weakened immune systems) put them at even more risk.

So how do you control or prevent mold growing inside?  The key here is that molds will grow if we give them the moisture and the nutrients they need; a basic rule of thumb is if we keep things dry, molds do not grow.  Here is a mold-proofing guide put together by the CMHC on how to mold-proof your home, room by room.

CMHC Guide To Mold-proofing your home, room by room

Basement or crawl space

  • Reduce the amount of clothes, paper and furnishings stored in the basement. Discard badly damaged materials. Eliminate clutter to improve air circulation. Only washable items should be stored.
  • Dehumidify the basement during the warm months.
  • Avoid carpets on slab-on-grade or below grade floors.
  • Periodically clean the drain in your basement floor. Use half a cup of bleach, let it stand for a few minutes, then flush with plenty of water. Keep the drain trap filled with water.
  • Avoid standing water. Keep sump pits covered (you can use plywood wrapped with plastic).
  • Regularly clean and replace furnace filters. Use a pleated one-inch filter, not a coarse filter.
  • If you have a heat recovery ventilator (HRV), clean the filter inside the HRV often.
  • If you notice molds or signs of dampness, such as water on your windows or wet spots elsewhere, do not humidify. Disconnect furnace humidifiers that are no longer used.
  • If you have electric baseboards, vacuum the units, or have a professional clean them for you.

Laundry areas

  • Check that your clothes dryer exhausts to the outside.
  • Remove lint every time you use the dryer.
  • Don’t hang-dry laundry indoors.
  • Dry your laundry tub and washing machine after you use them.


  • Check the bathroom fan to make sure it exhausts to the outside.
  • Turn the bathroom fan on when you shower. Keep it running for a few minutes after you finish your shower.
  • Take short showers.
  • Keep surfaces that get wet, such as the walls around the bathtub and shower, clean and dry.
  • If there is a carpet in your bathroom, remove it.
  • Check for water leaks.
  • Keep drains in good shape by removing debris from them.

To clean a drain:

  • Pour a handful of baking soda into it.
  • Add a cup of vinegar.
  • Put the plug in the drain.
  • Let the vinegar and baking soda work for about 20 minutes.
  • Run fresh water into the drain.

If the drain is still clogged, use a small plumbing snake.


  • If the fan over your stove exhausts outside, use it when you cook.
  • Minimize open boiling.
  • Keep your drains in good shape. Follow the steps in the Bathrooms section above.
  • There’s a drip pan at the back of the refrigerator. Pull the refrigerator out to clean the drip pan. At the same time, vacuum dust from the coils at the back of the refrigerator.
  • Check under the kitchen sink to make sure there are no leaks.
  • Take out the garbage daily to prevent odours and spoiling.

Closets and bedrooms

  • Get rid of clothes and other stored items that you don’t use. Keeping your closets and bedrooms tidy makes it easier for air to circulate — and harder for mold to grow.

Other parts of the home

  • A dehumidifier helps to reduce moisture in the home during the warmer months. Close the windows when the dehumidifier is running.
  • When family and friends come into the home, have them take off their shoes.
  • Vacuum often. If you are buying a vacuum cleaner, try to get one with a HEPA filter.
  • Clean hard floors with a damp mop.
  • Do not bring in furniture, clothing, books etc. that have been stored in a moldy place into your home.
  • Cut down the number of potted plants in the house—soil is a good place for mold.


  • Regularly check the condition of the roof and exterior finish for any places where water might enter.
  • Make sure that eavestroughs and downspouts are connected and working properly and that they are free of debris.
  • Install downspout extensions to lead water away from the building.
  • Deal promptly with any problems that you find.


  1. Thanks for sharing your thoughts about canister vacuum cleaners.


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