Why fasteners pop through the finish
Shrinkage isn't the only cause. The CGC construction handbook chapter on drywall problems says fastener defects are usually caused by improper framing or fastener application. It lists framing that is twisted or out of alignment, panels that weren't held tight against the framing while they were fastened, nails that broke through the face paper, and screws that stripped or didn't seat properly. A round bump tells you where to look, not which of these happened.
Timing matters too. The same handbook says pops that show up after a month or more of heating are usually caused at least partly by wood shrinkage, and it recommends waiting until near the end of the heating season to repair them. For homes in Northeast Philadelphia and Bucks County, that means pops that appear in winter may be worth noting and photographing now and fixing in spring, unless something else about them is a concern.
Why cracks follow drywall seams
Where the crack sits is a useful clue. USG separates cracks along the edges of the tape, which it links to compound drying too fast in hot, dry or drafty conditions or to a poor bond from cold, wet application, from cracks running through the center of a flat joint or an inside corner. Those center cracks, it says, are typically caused by movement, which can be thermal, moisture-related or structural.
When someone looks at the wall, ask them whether the tape edge has let go or the joint itself has opened down the middle. Both can start as a thin line, but they point to different causes and different repairs. Seasonal humidity can move other parts of a house as well, which our guide to a door that rubs in humid weather covers.
When it's mostly cosmetic and when to look further
A defect limited to one fastener or one taped joint may only need a local drywall repair, but calling it cosmetic should come after someone has looked at the cause, not from a glance at how wide the crack is. If cracks keep coming back after repairs, show up in several rooms, or appear alongside other changes in the house, ask whether a structural engineer should take a look before anyone patches over them.
When moisture changes the priority
A crack alone doesn't prove there's a leak. But USG notes that excessive moisture can soften the gypsum core and lead to loss of bond in joint compound and paint, so dampness near the crack should be dealt with before any cosmetic work. Peeling paint can be a sign of the same problem, as our guide to bathroom paint peeling off in sheets explains.
EPA's guidance on biological contaminants says to fix water and moisture problems promptly, to dry wet materials as soon as possible, ideally within 24 to 48 hours, to consider replacing materials that can't be cleaned and dried, and not to enclose, seal or paint materials that are wet or show signs of mold. If you suspect mold, have someone qualified find the water source and assess the damage rather than sanding or opening up the wall yourself.
What to document before arranging a repair
Take dated close-up and whole-room photos. Write down when the defect appeared, whether it's changing, whether it came back after an earlier repair, and any recent drywall work or water events. That gives whoever assesses it a history instead of a freshly covered surface.
Ask what the proposed repair actually fixes: loose panel attachment, damaged tape, or ongoing movement. The CGC handbook handles fastener and joint defects differently, and covering a bump with compound doesn't reattach a loose panel. Ask for a written scope that separates fixing the cause from refinishing the surface, and don't expect anyone to guarantee the cracks will never return. If the finished patch still shows after painting, our guide to drywall patches that show through paint explains why, and our contractor hiring checklist lists questions to ask before you sign.