If all framing were perfect, there would be little worry about screw or nail popping or cracks forming in walls over time. As a material, drywall is very stable. But wood structures expand and contract, so a discussion about minimizing fastener popping and cracking is important.
Why pop-outs occur
It’s common for houses and other buildings to be constructed with wood studs and joists with moisture levels as high as 19 percent. Michael Schmeida, the director of technical services for the Gypsum Association in Hyattsville, Maryland, says 19 percent humidity in wood building materials is the maximum allowed by most U.S. building codes. These moisture levels gradually decrease to about 10 percent as the wood in the building dries out, but drywall is often installed before drying occurs, and that can lead to trouble. Other contributing factors include:
- Drywall panels loosely attached to framing
- Twisted, bent, warped or bowed framing
- Incorrect fastener length
- Improper fastening
The most common reason drywall fasteners cause problems is the high moisture content of wood framing at the time drywall is installed. Schmeida explains that as the wood dries out, space can develop between the wood and drywall, especially when screws and nails of the wrong length are used.
Steel studs designed to accept drywall are very thin—typically 2 to 3 one-hundredths of an inch. If installers aren’t careful when they drive screws, they can cause spin-outs, resulting in loss of attachment.
Why drywall cracks over time
Wood framework constantly moves. Initially it’s mostly the result of wood with high relative humidity drying out to match ambient levels. Eventually, movement is limited to seasonal changes, wind, settling or seismic issues. The two most common places cracks develop are in large expanses of ceiling and inside corners around windows and doors—and cracks that begin in these areas tend to radiate out.
How to avoid problems
Here are some suggestions for better installations:
- For new construction, Schmeida urges contractors to enclose structures and turn on furnaces or air conditioners, depending on the season, for several days before drywall is installed to stabilize the environment and ensure proper drying of joint compounds.
- Use proper screw and nail lengths. If you are installing half-inch-thick drywall, use 1¼-inch-long drywall screws or 1-inch-long nails for the right amount of fastener penetration into framing members.
- Exercise care when screwing into steel studs to reduce spin-out occurrence.
- On ceilings with framing members exceeding 15 feet in length, use resilient channels to reduce cracks. They separate wood and drywall, allowing each to contract and expand independently of the other.
- Cracking mostly occurs where drywall pieces meet up with each other. Arrange for one piece to go around corners at doors and windows especially, so that no joint occurs at the corner—where the most movement occurs in buildings.
- Drive all screws or nails properly. Remove them if they miss framing members or if they go in at sharp angles. Drive fasteners so they go just below the surface without tearing the face paper of the drywall.
Joe Nasvik is a writer and editor serving the construction and concrete industries. He has 18 years experience as a concrete contractor. Contact him at email@example.com.
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