How To Repair Depressions in Drywall
Nail and screw depressions often are not visible until after the wall has been painted. They result when a fastener was driven too deeply and the depression was not properly covered. The repair is easy to make.
Start by sanding off any sheen from the paint, so that the joint compound will adhere better. Before patching, press on the drywall to feel for any movement. If you feel any movement at all, the drywall core is damaged and a new fastener should be driven nearby. It will be necessary to determine the location of the stud behind the drywall, so that you drive the new screw into a solid support. About 1.5" to 2" inches away from the popped fastener, drive a new drywall screw so that the head just dimples the surface of the drywall. As you begin driving the screw, use firm pressure with your other hand to snug the drywall against the supports. If the panel is now secure, proceed to the next step.
To cover the fasteners, use joint compound or other patching material.You could apply the material directly over the fasteners, however, the patch may chip out again or it may appear unsightly. A more secure solution is to apply a small piece of mesh drywall tape. The tape proves a substrate for the compound to adhere to, resulting in a smoother, stronger patch.
Remove any loose material from around the fastener and reset it if necessary. Use a 3" putty knife to fill the depression with joint compound. Next, cut a piece of mesh tape and adhere it over the fasteners and any surrounding damage. Next, using a 3" putty knife, spread a coat of joint compound over the mesh tape and allow it to dry.
After the compound has dried for at least a couples hours, lightly sand it smooth. Wipe away any dust and apply another coat of joint compound. Taper the compound at the edges to blend it with the surrounding surface. Allow this coat to dry and then sand.
Finally, apply a third coat of joint compound. With this coat, it will be necessary to blend it with the surrounding decorative texture. There are many different textures, so we can't list all of them here. However, matching a texture can sometimes be done by dragging the compound around with a putty knife, dabbed with a moist sponge, or sprayed on with off the shelf products designed to retexture small patches.