Date:29 June 2014
Q: Last weekend I was installing some 2 x 4 blocking for a bathroom cabinet in a drywall set-up, and I really struggled to drive the screws into the timber. In fact, whenever I use drywall screws to build stuff, they break or strip. Any suggestions? I’ve tried nailing, but there’s not enough room to swing a hammer.
A: Enough, already! Let’s just stop using drywall screws for construction. We’ve all done it. Yes, they’re cheap. Yes, we always seem to have a box or two of them handy. But they’re not multipurpose screws; they’re good for one thing, and that’s hanging drywall. They almost always snap when over-torqued or driven into hard, dry wood. (Fact: they’re engineered to be brittle, which suits the drive-and-go pace of the professional drywall installer. Who wants to extract a stripped screw from a sheet that’s halfway hung?) Ordinary wood screws aren’t helpful, either. They require you to drill a pilot hole, which is fussy and time consuming work.
Instead, we suggest picking up some Spax construction screws. These next generation fasteners are so well engineered and so effective that you’ll wonder how you ever managed without them. They’re available in different sizes, but the most useful ones are similar in diameter and length to a 16d (about 88 mm) nail. For example, Spax makes a No 9 screw that’s 82,5 mm long. You can use these anywhere you would a 16d nail, so they’re ideal for any projects that use dimensional timber.
You won’t need to bore a pilot hole, because these screws have serrated threads towards the tip that cut away wood like a saw. That also means you can drive them close to the end of a board without it splitting. On the underside of their bugle heads are ridges that cut a nice, neat countersink. Similar to the Spax are GRK fasteners (both of these brands are German), which also add a cut thread at the tip that helps get the screw started and another thread at the shank that enlarges the hole slightly to further reduce splitting. Because of all this clever engineering and because these fasteners are made of hardened steel, they won’t shear off under normal use. We’ve forced plenty into century-old, rock-hard timber, and typically the driver has given up well before the screw has broken.
Spax-type screws usually come packaged with a Torx T20 or T25 bit. These have star-shaped cross sections that make greater contact with the screw head than a Phillips bit, so they’re less likely to cam out.