Drywall nail pops are unsightly bulges in your walls that are usually about the size of a silver dollar. They are caused by drywall nails that have become loose in the wood over time due to loss of friction, seismic activity, wind, humidity, or vibrations caused by loud music or nearby roads with lots of traffic. Nail pops usually aren't a problem in newer homes, and by using drywall screws instead of nails, you can greatly reduce the chance of your walls incurring nail pops over the years. However, here are some guidelines if you encounter this problem.
Peel away the paint around the area where the wall is bulging out. If it is too difficult to do so by hand, use a putty knife to get the job done.
Locate the nail head, or screw, which is causing the bulge in the wall. If it is a nail, use your hammer and nail set to drive the nail back into the wall until it is countersunk about 1/8 of an inch into the wall. If it is a screw, use a screwdriver to do the same.
Mix some drywall setting compound, which is in powder form, with some water according to the instructions on the package. You can also substitute a premixed drywall compound, but the powder variety usually works better and lasts longer.
Apply the mixture to the nail head and surrounding area with the putty knife, and smooth it out. Allow it to dry until hard.
Use the sandpaper to smooth out the now dried drywall compound. If the wall feels smooth after sanding, no more coats of drywall compound will be necessary. If the wall looks bumpy or you can still see the nail head, apply one or two more coats of the drywall compound by repeating Step 4.
Apply a smooth coat of primer with a paint brush and let dry. Two coats may be necessary if you can still see the nail head after the primer has dried.
Paint the area you have just primed with a colour that matches the rest of the wall. If you don't have leftover matching paint to use for this step, take a large paint chip to your local paint store, and an associate should be able to match it for you.
To reduce the chance of the nail popping again, drive one 1-1/2 inch screw 12 inches above, and one 1-1/2 inch screw 12 inches below, the nail pop for extra support. Drywall screws will not pop nearly as much as nails, so they may be the better option.
Paint and primer should be used in a well-ventilated area because of potentially dangerous fumes.