Being on the Watch for Household Dampness

One good way to investigate dampness is by walking around the home during a rain storm. Check the following:

  • Gutters should be clear and draining properly. Overflowing gutters are a common problem.
  • Downspouts should not flood water next to the house. Add an extension (leader) to discharge the water well away from the home.
  • Downspouts that discharge below grade should be checked very carefully. Make sure water is not leaking into the soil or backing up into the basement through the floor drain. In some cases it is prudent to disconnect downspouts that discharge below grade and redirect the water away from the house instead. 
  • Land around the house should shed water away from the house for at least six feet.

How do I know if my home is damp?

Signs of high levels of internal moisture are:

  • Mildew
  • Condensation on hard surfaces
  • Water stains.
  • Swelling and rotting wood or wood-based materials.
  • Rotting carpet
  • Bubbling wall linings and vinyl floor coverings.
  • Musty smells.


Mould is known to cause inflammation, allergies and infections.

It is a relatively straightforward process to remove mould from hard non-porous surfaces such as glass or ceramic tile. Removing mould from porous substances such as wallboard, wood and carpets is more difficult and more hazardous. This is because spores can be released when disturbing rotten material and these can cause inflammation, allergies and infections.

New Homes

In new buildings, some moisture is trapped during the construction process. Wet timber may also have been used. This will dry out eventually over the first year of the building’s life, as long as the house is properly heated, ventilated and insulated.


Showers, cooking, especially on the stovetop, flueless gas heaters, and indoor drying of clothes all create large amounts of water vapour leading to condensation.

The best remedies are to reduce the amount of moisture or extract moisture as close to its source as possible. Some good ways to reduce condensation include:

  • Not drying clothes indoors.
  • Putting lids on pans when cooking.
  • Using extractor fans when cooking or showering.
  • Keeping your showers short.
  • Cover fish tanks.
  • Choosing household plants that don’t require a lot of water – for example, yuccas, succulents and dracaenas.