Checklist: Moisture Problems in All Living Areas

Window sill with water damage and peeling paint

Typical Signs

  • Condensation on windows.
  • Rotting windowsills.
  • Damaged gypsum board and bubbled or flaking paint.
  • Musty smell.
  • Mould on walls.
  • Mouldy drapes, carpets or furniture.
  • Mould in closets.

Possible Causes

  • Poorly set and controlled humidifiers.
  • Excessive moisture from damp basement or crawl spaces.
  • Many moisture-producing activities by occupants — cooking, bathing, washing.
  • Too many people/pets in the home.
  • Uncovered aquarium.
  • Large number of plants.
  • Firewood stored inside.
  • Poor air circulation between rooms or within a room.
  • Cold surfaces due to inadequate insulation.
  • Large air leaks at electrical fixtures and outlets, window frames, etc.
  • Closed drapes preventing warm room air from warming window surfaces.
  • Closet contents stuffed against colder exterior walls.
  • Rooms kept too cool, programmable thermostats setback too aggressive.
  • Inadequate ventilation, ventilation equipment not used.
  • Air conditioner poorly maintained, condensation on cold water pipes during the summer.
Person caulking the space between a floor and wall

Practical Solutions

  • Discontinue or control humidifier use.
  • In summer use a dehumidifier.
  • Fix sources of moisture in basement or crawl space.
  • Install and use quiet, energy-efficient kitchen and bathroom exhaust fans.
  • Cover aquarium.
  • Reduce number of potted plants or make covers for the soil.
  • Circulate air between rooms by running furnace fan continuously on low speed. Ensure air can circulate within rooms — particularly over colder surfaces.
  • Properly insulate cold surfaces.
  • Wipe up condensate that may form on windows during colder weather.
  • Seal air leaks.
  • Reduce stored items — particularly those in proximity to outside walls, basement floors that limit air circulation.
  • Open drapes and blinds to promote air flow over windows.
  • Ensure 2.5-cm (1-in.) gap at the bottom of closets and doors; leave closet doors open during cold weather.
  • Provide heat to all areas.
  • Install a balanced ventilation system, such as a heat recovery ventilator, and use it regularly.
  • Keep air conditioning drip pans clean and the drain lines unobstructed and flowing properly.



Print(opens in a new window)