Paint keeps cracking over my drywall repair - what am I doing wrong?

Posted by jenn_reno2026 on February 2, 2026 at 2:22 PM

repaired a big crack in our hallway wall about 3 weeks ago. used mesh tape and 3 coats of joint compound, sanded it smooth, looked great. painted over it and within a week the paint started cracking right along the repair line. so i sanded it back down and repainted. cracking again in the same spot. im losing my mind here lol. is the joint compound still drying underneath or something? the crack was maybe 4 feet long running diagonally from the corner of a doorframe

7 Comments

MudMaster_Greg Feb 2 at 3:08 PM

Did you prime the repair before painting? Raw joint compound absorbs paint differently than the surrounding wall so the paint film doesnt bond right. PVA primer or a good sealing primer like Kilz should go on first. That alone might fix your problem.

jenn_reno2026 Feb 2 at 3:34 PM

i did not prime it. just painted straight over. that would explain why it only cracks on the repair and nowhere else right?

MudMaster_Greg Feb 2 at 4:10 PM

yep exactly. the mud is way more porous than the existing painted wall so the paint dries differently on the patch vs around it. prime it with a roller, let it dry fully, then paint. should solve it

tapeAndFloat Feb 2 at 4:45 PM

Also that diagonal crack from a doorframe corner is almost always a structural stress crack. the house settles and it opens right back up. mesh tape is bad for this because it has no real strength against movement. you want paper tape for stress cracks because it resists tearing way better. might need to redo the tape tbh

weekendDrywaller Feb 2 at 7:55 PM

had the exact same issue at my place. diagonal crack from doorframe, kept coming back. what finally worked for me was scraping out the old repair, using fiberglass mesh tape with setting compound (the powder you mix, not premixed), then paper tape over that with regular mud. overkill? probably. but its been 2 years and no cracking. also definitely prime before you paint

tapeAndFloat Feb 3 at 8:22 AM

setting compound is a great call for this. hot mud doesnt shrink like premixed does so less chance of the crack telegraphing through

PaintPro_Carla Feb 3 at 11:40 AM

One more thing nobody mentioned yet. If you painted with a cheap flat paint thats going to show cracks way faster than a satin or eggshell. Flat paint has zero flexibility. I always use eggshell minimum over repairs because it can flex a tiny bit with the wall movement. wont fix a bad tape job but it helps with hairline stuff