my Old Workshop

How to install deck boards straight and true

If you’re building a deck, you might think it’s easy to line up those deckboards nice and evenly. Until you get started, that is. First off, even good dry lumber isn’t always straight. And since the width can vary slightly, your boards can veer off course as you go along.

Here’s some help. Start by snapping chalklines for every three boards. Total the width of three deckboards and the space between them (x3). Snap a chalkline across the joists where your first board will lie, then measure the three-board distance, and snap another chalkline. Continue to the end.

Now, using the straightest boards you have, nail them along each chalk line. You’ll have space for two boards between these rows, but since you have nice straight guides, it’s easy to eyeball where they’ll fit.

Of course, you’re going to find that some boards are warped along their length, and need to be forced into alignment.

To push a warped board away from a securely nailed board, begin nailing from one end, prying with a chisel or prybar as necessary, and nailing in place.

You can also straighten stubborn deckboards by using a strong nylon tiedown strap with a locking buckle. Wrap it around the warped board and the board nailed next to it. Cinch the belt tight till you’re satisfied, then nail in the board.

Here’s a final tip from the cabinet maker’s toolbox. If you have to butt two boards together, you can get a much tighter-looking joint by slightly undercutting or bevelling the end-cuts so the top surface of the deckboards touch each other. It’s also important to make a perfect 90 degree cut, and a speed square comes in handy.