Some Solutions For Separation Situation - January 23rd 2012
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 moulding?
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 (Air Leakage) causing expansion of the bottom cord of the truss system. The expansion of the bottom cord causes the ceiling to go up. To correct this you must draft proof your ceiling cavity. For more information, Natural Resources Canada has a pamphlet dealing with Air Leakage Control. This brochure contains easy to follow instructions to correct your problem.
Before installing your crown mouldings, first apply a bead of draft seal caulking to the joint where the ceiling and wall meet. When you install your new mouldings 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 mouldings are wide enough, it will cover the crack along the ceiling.