Drywall screws are plentiful and cheap. Since they are used in great quantities, they come in great quantities–which means that they always seem to be at hand. Can you build with drywall screws? Or are they too weak for anything but hanging drywall?
Yes, you can use drywall screws for light building projects around the home.
It is heretical to say that drywall screws can be used for building. If you’ve ever opened a box of drywall screws and seen the duds–heads snapped off in production and random bits of metal–this may give you some pause.
Snapping Off (Shear Strength)
True, drywall screws snap. This cannot be denied. With drywall screws, it’s all or nothing. Either they’re holding or they have broken apart, unlike steel or brass screws or nails which bend before breaking.
Tension Pull-Out Strength
Some evidence shows that drywall screws have roughly half the tension pull-out strength of steel self-drilling screws.
Benefit vs. Risk
The benefit to you may outweigh the risk of using drywall screws to build with. Benefits include: they are inexpensive; coarse-threaded drywall screws easily pull into wood; driver grips screw heads well. The risk is that your kitchen cabinet falls down.
Light Building Only: Using drywall screws for any type of heavy building project, like framing a house or setting a beam to replace a load-bearing wall, would not be a good idea, to put it mildly. Used in great numbers, the drywall screws would still likely have enough redundancy to hold up the roof or wall. But given the safety issues, it’s just not worth it to go this route.
Indoors Only: Drywall screws have a black or gray phosphate coating that does not stand up to moisture well. As Grabber Canada says, “Phosphate is a porous coating, which is usually applied in combination with oil. It is the lowest cost of all fastener finishes and as such, offers only a minimal barrier to corrosion . It is suitable for indoor applications only, where there is minimal chance of exposure to moisture.”
Impact vs. Resting Loads: Because drywall screws have such a tendency to snap upon sharp impact, you would want to avoid using drywall screws for any building project that involves sharp movements.
Interfast Group, a fastener manufacturer, published some data about pull-out tension strength of their drywall screws vs. other types of their screws.
Matthias Wandel, a Canadian woodworker and former software engineer, takes a methodical, measured approach to the issue of drywall screw tensile strength and pulling ability. He found that drywall screws snap off when hit by a hammer from the side and that they have good gripping strength.
Grabber Canada, a fastener manufacturer, offers some technical data about drywall screws’ strength.
Most opinions about the wisdom or not of using drywall screws for building are anecdotal, and go both ways. One commenter on Sawmill Creek asks, “has anyone actually seen catastrophic failure from a cabinet installed with drywall screws?” Another says, “I put the cabinets in my garage 20 years ago and hung them with drywall screws and have had zero problems.”