Install Passive Vents in Garage for Humidity - July 12th 2005

Install Passive Vents in Garage for Humidity

Q: We have a problem in our garage. Our home is around 6 years old and when it was built the outside walls and ceiling were insulated, and an insulated garage door was installed. The garage has one window that does not open. I have noticed mould on the window sill and condensation on the window during the cold winter days, and I find the garage very warm in the summer. I am not sure what to do to correct the problem. I think it either needs an opening window or a fan to remove the humidity or possibly both.
Jeannette, West Vancouver

A: This is a great question and one that is asked about garages quite often. I would recommend that you install 2 passive vents at least 8" x 8" or up to 12" x 12 inches square. These can be gable vents available at your local Building Supply store. Install one 4 - 6 inches down from the ceiling between the wall studs on the side (just below the wall plates) and another one above the snow line as you do not want to have snow build up over the openings. On the other side or back or either side of the garage door install the vent approximately 12 inches up from the concrete floor. These vents allow moisture and air to move in and out with expansion and contraction air displacement throughout the year.