By Mark Clement
We can make all the most perfect cuts ever building that swing set or pergola or arbor, but if we don’t have the right fastener holding it all together, well those cuts and closed joints will 100% wiggle open in short order. Or the connection will work, but just doesn’t look right.
And when it comes to making what we call “structural connections” these need to work better than well—through seasons and over time. Outside. If you’re building something like a deck, there are very specific code requirements of how many and where to use them. More on that later.
A Bolted Connection
For the most part, what has typically been a bolted connection—say carriage bolts for a playset or DIY swingset or guard posts in a deck—can be made with modern and utterly awesome “structural screws”. There is an enormous amount of science (warning: I geek out here a little) that goes into designing these things. Oh, and a quick aside, one of the best books I ever read was about the screw and how it shaped the last two-thousand years—how it literally made the device you’re reading this on possible. Let that sink in a quick sec. It’s called One Good Turn. Looking for a gift for a hard-to-please DIYer, try this.
The Impact Driver and Structural Screws
OK, back from geekery: Structural screws are not quite a typical lag screw you buy (along with a washer) from the bulk hardware section of the home center. Structural screws are typically branded and sold individually labeled or in boxes. And they’re great for a whole host of things, however, they might not have made as big an in-road as they have were it not for a tool that just a few years ago was not an every day item for many DIYers: An impact driver.
Impacts put the power in your hands to drive these ¼-inch and 5/16-inch shank screws into mountains of wood getting a connection I call a “wood weld”. I mean the connection is just fused together.
These screws are coated for use with pressure treated lumber and exterior applications. So if you’re building a stacked 6×6 retaining wall, rather than pre-drilling holes and pounding 60-penny spikes or re-bar in there, they can be screwed together. No pre-drilling required either.
Where you’d normally use bolts—say for a swingset—the wood can be screwed together and no bolt heads are sticking out.
Some brands are even making decorative elements for screws and brackets. They’re really cool and certainly add a post-and-beam feel to a backyard build.
Follow the Rules
When it comes to structure—deck ledger boards, post-to-beam connections and guard posts mainly—check with your local building official what is allowed where you live. No deck should be built without a permit anyway. However, the last few decks I built the old drill and drive bolt-washer-nut assembly is now a quick drive of a few screws.