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Lisa21276
Ceiling seperating from walls

In the winter time, our ceilings seem to lift off of the walls creating a gap between the crown molding and the tops of the walls. As summer creeps nearer, the ceilings settle back onto the walls. If we caulk the edges, come winter time, the gaps reappear. What could be causing this? My husband thinks it might have something to do with the heat in the attic and the roof not being vented properly. Thanks for any help We live in central North Carolina.

goldhiller
Re: Ceiling seperating from walls

Lisa,

If your roof is comprised of trusses, then truss-uplift is almost certainly the cause. But truss uplift doesn't need to make your ceiling joints crack open. It's up to the drywall installers to fasten in such a manner that this cracking doesn't occur. The simplest way to avoid cracked ceiling/wall joints from truss uplift is to keep the ceiling drywall screws that are near a ceiling/wall joint approx. 18" away...and no closer. The perimeter of ceiling drywall simply rests on the upper edge of the wall drywall leaving the tape & compound to secure the two together. When the trusses move, the ceiling drywall will/can bend a bit, but no crack appears.

http://64.233.167.104/search?q=cache:e2tJIdE4BlYJ:www.buildingscienceconsulting.com/resources/walls/dywall_wood_truss_uplift.pdf+truss+uplift&hl=en&ct=clnk&cd=1&gl=us

If your vaulted roof framing is stick-built (comprised of 2x12s or similar), then the cracks you're referring to are likely only seen on the outside walls of the house and not on interior parition walls. If this is the case, then the cracks that are appearing are almost certainly due to normal expansion and contraction of the 2x12-ish rafters as the seasonal humidity levels vary.

The same basic causes and remedies prevail. Find and remove the screws that are too close or.......consider mounting some crown molding or similar to hide the problem. However, if you try the latter....be aware that you can only fasten/nail the molding to the ceiling and not at all to the walls. This will allow the molding to move up and down with the ceiling while still covering the visual offensive cracking. But if you fasten both the top and bottom of the molding, the molding itself will split and you'll have another/different crack to look at.

Google - truss uplift - for much info on the phenomenon.

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