In the winter of 1995 and spring of 1996, the CMHC (Canada Mortgage and Housing Corporation, Canada's National Housing Agency), conducted a survey of 405 houses in the Ottawa region of Ontario, Canada. The objective of the survey was "to determine whether typical 'finished' basements are contributing to poor indoor air quality as a result of mold growth in the finishing materials".

About half of the 405 houses "had signs of moisture in the basement". The study then selected 22 for further investigation. Molds were found in 18 of the 22 houses, or 82%. Mold samples were taken from 16 of the 18 houses. In 100% of those houses, "molds with properties that are harmful to humans were found."

The study concluded:
"1. Some finished basements do present health hazards to the occupants due to the presence of toxigenic and dangerous molds in the wall cavities;
2. The causes of mold growth in finished basements are directly related to chronic wetting incidents rather than the wall finishing and insulating techniques;
3. The main chronic moisture sources associated with mold growth in finished basements are exterior moisture sources and wetting mechanisms..."

Click here for a test on the quantity of water entering a building through concrete wicking action.

Click here for the full CMHC report entitled "Molds in Finished Basements".

Click here for a copy of the Fab-Form report showing how rising damp can contribute to chronic wetting in basements.