Cracks in Sheetrock

I recently started remodeling a frame house build in the 60’s. We repaired all the sheetrock and blew mud on the the ceiling and walls and it was not a heavy coat. Several weeks after it was dried and painted we started seeing cracks mainly in the ceiling but some on the walls.

The cracks in the ceiling did not follow the tape lines. They may be in middle of the sheet and cruvey. We went into the attic and place boards across the cracks between the joist and screwed the sheetrock to the boards. Now a week later we are getting new cracks and now on the walls. The cracks on the walls are the type that will show when the house settles.

We have had a real hot and dry summer but then we started getting 1 to 2 inches of rain at a time. The latest cracks showed up after the rain. I have seen cracks along the seams but never in the middle of the sheets. what could be causing this? I hope I dont have to resheetrock the entire ceiling.

Our Answer

I need some clarification on these cracks.

Ceiling. Are the cracks all the way through the boards or just surface cracking?

Surface cracks are caused by the mud you placed on the boards themselves. Pre-mixed mud shrinks a lot and is not the correct material to use to put textured finishes on with. You need the type that comes in a bag that you mix your own water with. This material shrinks much less, is harder and lasts much longer. The pre mixed material in the buckets is not supposed to be used in thicker layers. It takes a long time for this to dry. And as it does it shrinks a lot. This is why you only put this on in very thin coats.

On the walls. If the cracks are showing up and is consistent with the seams of the boards, Did you use tape on the joints? Also when doing sheetrock on walls around doors and windows, ideally you do not want a seam to end on a corner. The boards should be cut into L shapes to wrap around the corners of the windows and doors. This provides a much stronger corner that is much less prone to cracking.

In any case are the cracks on seams? Or are they at an angle to the opening starting at the corners of openings? Are these cracks all the way through the wallboard, or just surface types?

Houses shrink and swell with weather all the time. And based on humidity factors within the home everything tends to move about the same rate so cracking from expansion and contraction of the framing members is doubtful Not saying it does not happen, but long before it gets that bad you will see lots of nail spots showing up as that is where the fastening takes place. And the boards will simply pull loose on these locations first.