Paul in Calgary, Alberta has a partially finished basement and wants to complete the job now, but he has one stud covered with black stuff. Is this mould? Is this serious?
It is probably mould and it is probably serious. Put a little laundry bleach on it. If it changes colour, it is most likely mould. Any mould mass must be scraped off and the rest cleaned. At the time of this TV show, it was recommended to use a bleach water mixture, but with new research it is now recommended to remove ordinary mould with simply an unsented detergent and water. Follow this link to MOULD to see why the change. If the mould goes deeply into the wood, the piece should be replaced.
For free pamphlets on dealing with mould in your house, contact the Canada Mortgage and Housing Corporation.