The protrusion of screw or nail heads above the gypsum panel surface is caused by one or moreof the following:
- Lumber shrinkage occurring after gypsum panel product application,
- Loose attachment of the gypsum panel product to the framing,
- Improperly aligned, twisted, bent, warped, or bowed framing,
- Incorrect fastener length, or
- Improper fastening
Fastener pops are largely caused by lumber shrinkage due to initially high moisture content lumber.
Overly long fastener length contributes to the problem and fastener penetration into wood framing should not exceed 7/8 in. (22 mm) for nails, 5/8 in. (16 mm) for screws. For fire-resistance rated systems use fastener lengths specified in the listing. Fastener pops that appear either before or during decoration should be repaired immediately.
Those that appear one or more months into the heating season are usually a result of lumber shrinkage and should not be repaired until the end of the heating season.
Fastener pops are repaired by reattaching the gypsum panel product to the framing by driving a new screw or nail of the proper length into the same framing member about 1-1/2 in. (40 mm) from the popped fastener. Apply sufficient pressure to the gypsum panel to bring the back surface into firm contact with the framing member to which it is being reattached. Remove the fastener or reseat the popped fastener so that it is just below the face of the gypsum panel. Remove any loose material before treating with joint compound and redecorating.