We have a problem in two bedrooms. Above the garage, the carpet nail strip seems to be leaving black marks on the carpet. The house is now 8 years old and this problem appeared approximately 6 years ago and it seems to be getting worse. Our carpet is a light cream color so it is very noticeable. Is there anything that we can do?
You need to draft proof your home along the underside of your drywall in behind the carpet smooth edge nailing strip. Pull the carpet off the smooth edge and using a draft seal caulking tube, apply the caulking under the drywall board up against the bottom plate and sub floor plywood (or shiplap).
For more information on draft-proofing, contact Resources Canada 1-800-387-2000 for a free copy or their Air Leakage brochure.