Q. We live in a one level rancher and we would like to take care of a problem that occurs every year. Every winter the ceiling is separating from the wall and sets itself back into place in the summer. Is there something I can do to correct the problem before we install our new crown molding?
A. The seasonal opening and closing of the joint between the ceiling and the wall
is caused by roof truss movement or truss uplift. This is caused by inadequate roof cavity ventilation and air leakage. During the heating season, warm moist air is carried into the ceiling cavity causing expansion of the ceiling joists or bottom cord of truss system. To correct you must draft proof your ceiling cavity. For more information, contact Natural Resources Canada at 1-800-622-6232 and order their pamphlet dealing with Air Leakage Control. This pamphlet contains easy to follow instructions to correct your problem.
When you install your new moldings nail them to the ceiling, not the wall, as is typically done so they are free to move up and down with the ceiling. If the moldings are wide enough, it will cover the crack at the ceiling along the ceiling.
Q. We live in a doublewide manufactured home that has two whirly bird vents on the roof that were installed by the previous owner. The whirlybirds do not require much of a wind to start going but there cannot be much more than a foot or two between the roof and ceiling since it is a low pitch metal roof. The fans make a lot of noise and in colder weather; we notice quite a substantial draft down the hallway. The bedrooms at the rear of the home are also quite chilly, also perhaps part of a draft problem we have.
With such a small space between the outer roof and the ceiling, would you think that the fans are of much benefit in summer or winter should we remove them?
A. My suggestion would be to cover the whirlybird units with a heavy-duty plastic bag for the fall and winter months. I seldom recommend whirlybird vents on a modular home because by and large, the ceiling is not draft proofed and can become drafty. A basic rule of thumb on a modular homes built to factory specs is that if extra venting is required, it would have been put there at the time it was built. Try covering the vents instead of removing them at this time since it will be less costly.