- Q.We're getting more nail
pops in our drywall applications this year than ever
before. I've been told that as wood gains moisture, it
swells and squeezes the nail out of the nail hole. Are
all these nail pops caused by excessive moisture in the
house? How can we prevent them?
Paul Fisette responds: Nail pops are related
to changes in the moisture content of your framing,
but they're a sign of moisture loss, not moisture
gain. Pops generally result when drywall is
fastened to the face of framing material with a
relatively high moisture content. As the studs dry,
they shrink. The point of the fully driven drywall
nail stays positioned within the stud at the depth
it was originally driven, but the face of the stud
or framing member shrinks along the shaft of the
nail toward the nail point, leaving the head of the
nail proud of the drywall surface.
The shorter the penetration of the nail tip into
the wood, the less shrinkage along the shaft of the
nail, and the less noticeable the nail pop will be.
So one way to minimize the magnitude of pops is to
use the shortest nails allowed.
The best advice, however, is to use dry framing
lumber. Do not use lumber that is stamped S-green
-- that stands for "surfaced-green" and indicates a
moisture content greater than 19%. Instead,
purchase lumber that is either kiln dried (KD) or
S-dry (which indicates a surface moisture content
of less than 19%).
You must still verify that the lumber has been
kept dry in storage and is as close as possible to
the in-service moisture content you want (about 12%
to 14%). You can verify that with a moisture meter.
Also, it's better to use drywall screws instead of