How to fix a crack in the ceiling

for full fix, sand to remove paint, re "paper' the crack with the product made for that purpose, several coats of 'mud', sanded, then repaint. A pain.

*Note* My home is in the south, with high temperatures and high humidity and it was also built in the 50’s.

When I bough my home it had a huge crack that we tried fixing with sheetrock tape and spackle. It worked for a while but as time went on the crack grew to the point that we were worried the ceiling would fall. When we first moved in we had blown insulation into the attic so we couldn’t take down the old Sheetrock or we would be covered in it. My husband and I decided the best fix was to use very thin smooth plywood sheets and screw them on the ceiling into the studs/beams. You can then fill the screw holes with puddy and sand, then paint the plywood or put ceiling tile up. It was a lot of over head work and even though it was a bit hard, the hardest part was holding the big sheets. It works best to have three tall adults but we did most of it with him and I and I was also 3 months pregnant at the time. Our electricity bill wents down a lot after this fix, since a lot of our heating and cooling was seeping into the attic. Good luck!

Possibly a poor professional, OR movement of the house structure. I would consult a local contractor with what you said.