Really. It happens even in the dry winter on the prairies. Like most prairie homeowners, our long cold dry winters can cause indoor air to be too dry triggering dry eyes, nasal and throat discomfort. We compensate by adding humidifers, cooking without using stovetop fans, turning off our heat recovery ventilators (HRVs), etc. to try to increase the moisture in our homes.
Humidity is Good for Humans But Not for Houses
The humidity may be good for humans but not for houses. Too much indoor moisture can lead to mold problems by water vapour collecting on ceilings and walls (so called "sweating walls and ceilings") or water vapour turning to frost on windows and doors. If water vapour collection persists, it can lead to costly mold and water damage.
Common Causes of Moisture Build-Up in the Home
Mould will grow indoors if moisture is present. Moisture problems in homes may result from:
- daily activities such as showering or bathing, washing clothes or cooking, if exhaust fans are not working properly or are not used;
- infiltration of water from the outside when there are cracks or leaks in the foundation, floor, walls or roof;
- plumbing leaks;
- moisture condensation on cold surfaces;
- flooding due to weather conditions (snow melt, storm surges, prolonged or heavy rainfall);
- inadequate ventilation.
Moisture indoors accumulates when it cannot be vented outside and becomes a problem when building materials become damp or wet.
Moisture problems are preventable
Unless the cause of the moisture problem has been identified and solved, mould will reappear. Once the moisture problem and its causes have been identified, they must be fixed. To prevent future problems, measures should be put in place to control sources of moisture in your home, for example:
- Ensure rain, irrigation water and snow melt drain away from the house by sloping the grade away from the building.
- Keep eavestroughs and downspouts clean of debris and ensure that the outflow runs away from the house and not into neighbouring foundations.
- Repair plumbing leaks promptly.
- Use exhaust fans, ventilation and air conditioning systems to vent moisture outdoors.
- Use moisture tolerant materials in areas likely to get wet (kitchen, bathrooms, laundry areas).
- Use a hydrometer (pictured) in your home to help measure indoor moisture levels.
Run a dehumidifier in damp areas such as basements or if you observe that moisture is condensing on cold surfaces such as window panes.
The key to mould prevention is to remove excessive moisture build-up and control relative humidity through proper home maintenance and by following these steps:
- Remove the moisture by using an exhaust fan when you shower or take a bath.
- If you don't have an exhaust fan, get one installed in each bathroom.
- Check exhaust fans to make sure there is adequate air movement and that they are vented to the outside and not into the attic.
- Keep the fan running for at least 30 minutes after your shower.
- Keep surfaces clean and dry. Squeegee and dry the walls around the bathtub and shower after showering or bathing.
- Remove any mould by scrubbing with unscented dishwashing detergent and water.
- Clean often to prevent small patches of mould from getting larger.
- Repair or replace open, cracked or damaged tile, grout and caulking around showers and tubs.
- Repair plumbing leaks promptly.
- Remove the moisture by using a kitchen range hood every time you cook.
- Check the range hood to make sure there is adequate air movement and it vents to the outside.
- Cover pots with a lid while cooking.
- Check that your clothes dryer vents to the outside.
- Seal the joints in the dryer duct with foil tape.
- Clean the lint tray every time you use the dryer.
- Occasionally inspect the outside vent hood and remove any built-up lint.
- Make sure nothing is placed in front of the vent outside and that the vent is kept clear.
- Leave the washing machine door open when not in use so that any water left behind can dry. This will prevent mould and bacteria from growing inside the washing machine.
- Make sure that water from the washing machine flows directly into the laundry sink or drain without dripping or splashing outside of the laundry sink. Use pipe extensions to reduce any splashing.
- Check hoses and connections for leaks.
- Hanging wet laundry indoors increases indoor humidity.
Condensation on windows, window frames and sills
- Promptly repair any leaks.
- Lower the indoor moisture levels.
- Use exhaust bathroom fans and a kitchen range hood.
- Keep window coverings open to move the warm air over the windows (heavy curtains or blinds can trap the cold and moisture and cause condensation on your windows).
- Keep baseboards or heating vents clear of furniture to make sure the heat flows.
- Dry your window frames and sills daily to keep water from dripping and causing mould to grow.
- Leave interior doors open for good air and heat flow.
- Unplug and remove humidifiers.
- Run a dehumidifier (pictured) in your basement to help reduce dampness year round (if necessary). Make sure the windows are closed when the dehumidifier is running.
- Check plumbing pipes for condensation, dry pipes and insulate them with foam insulation.
- Keep areas and storage spaces free and clear of clutter, especially if near an outside wall.
- If you use the basement for storing items, use plastic bins with lids instead of cardboard.
- Never place cardboard boxes directly on the basement floor.
- Store firewood in the garage or shed, not inside the house.
- Remove any carpets from the basement floor.
- Have family and friends take off their shoes at the door before entering your home.
- Keep beds, bedding and furniture away from outside walls for good airflow.
- Keep closets and storage spaces free and clear of clutter, especially if near an outside wall.
- Install a central vacuum vented outdoors or use a HEPA vacuum. Vacuum often. Clean hard floors with a damp mop.
Last ThoughtsYou may also want to view Pacesetter Home's quick video to learn more about how to properly use your heat recovery ventilator (HRV) to help reduce indoor moisture.
Remember, humans may prefer moisture to improve indoor air quality but it could lead to costly home repairs.