Most wall cracks are the house breathing. Hairline cracks along drywall seams, tiny lines at the corners of doors and windows, and slight nail pops are settlement and seasonal movement — cosmetic, fillable, nothing to lose sleep over.
Pay attention instead to cracks that are wide enough to slip a credit card into, that run diagonally in a stair-step pattern through brick or block, or that keep coming back bigger after you’ve filled them. Add doors or windows that suddenly stick in a house where they never did, and floors that feel newly uneven — together, those point to movement in the structure itself, and that’s an engineer’s question, not a filler question.
Honest rule of thumb: fill the cosmetic ones yourself in an afternoon; get the others looked at in person before you decorate over the evidence. If you’d like a second pair of eyes, CMG Bridge serves Staten Island, Monday to Saturday — email handyman@cmgbridge.com or see our FAQ page.