Cause: Most likely a sheetrock seam that hasn't been screwed tightly, or simple house settling.
Repair: Put some 1 1/4" drywall screws into the area, to re-attach the sheetrock tightly to the stud (if that is the cause). You could also use a 'stud-finder' to locate the stud location.
Coat crack with mesh or paper tape. If using paper tape, make sure that you get plenty of compound under it to leave NO dry spots.
Re-coat smooth, let dry, sand lightly.
Repeat the last process............
.... until it is well coated and you can no longer see the tape outline. Each coat should be a little wider and smoother.
The best compound to use is the quick dry, that you mix up yourself....and yes, you can compound over a painted wall. The only issue you run into is: Whatever kind of compound you use takes alot longer to dry over the paint.
Last edited by AtlanticWBConst.; 08-08-2006 at 08:33 AM.