7 Deck-Building Tips

1. Make a Joist Jig
The easiest method for running deck joists, especially when you’re working alone, is to attach joist hangers to the ledger board before installing your joists. The trick is to set them at the right height. Take a few minutes to tack together the jig shown here.

Click image to enlarge.

Cut the 2x4 to the average width of the joists (sometimes the joists will vary in width as much as 1/4 in.). Nail both sides of the hanger flanges to the ledger, leaving one side with about a 1/16-in. gap so a wet joist can slide into place. As you set your joists, chisel out a notch on the bottom if the joist sits too high or shim it if it’s too low.

Construct a simple jig with a 5 x 12-in. piece of plywood and a scrap 2x4 cut to the width of your joists. Align the 2x4 to your layout line. Tack the plywood to the top of the ledger, making sure it’s tight. Place the joist hanger around the 2x4 and nail 16d galvanized nails through all the holes into the ledger board.

2. Accurate Notching
The most accurate way to cut a deck board around a post is to lay it in position against the post and transfer the post location directly onto it. When measuring for the depth of the notch, check both sides of the post. Oftentimes there’s a twist in the post and the measurements aren’t equal. Cut out the notch with a jigsaw.

Hold the deck board tight against the post. Transfer the post location to the board with a combination square. Measure and mark the depth of the notch.

Cut out the notch with a jigsaw, holding the base at a slight angle to back-bevel the cut for a tight fit.

3. Space Balusters With a Jig


Carpenters love to use jigs because they make work easier and faster. Here’s a simple jig that comes in handy for building rail sections (see illustration). It centers the baluster on 3-1/2 in. wide rails and sets the space between them typically 4 in. or less. When you attach the balusters, always start in the center so the leftover space on each end is equal. Measure the total length in advance and either start with a baluster in the exact center or with an opening centered (below)—whichever makes the space between the last baluster and the post come closest to your 4-in. maximum baluster opening.

Click image to enlarge.

Start at the center of the rail and work toward the ends, spacing each baluster with the jig. Support the other end of the balusters with a 1-in. thick board. Screw the balusters through the stringer with 3-in. deck screws.

4. Hanging Stronger Stair Stringers
Of the half-dozen deck stair-hanging methods I’ve tried for 2x8 framing, this method works the best. Cut the 2x12 stringers extra long and secure them to blocking between the joists (below) or to the joists themselves if they run parallel to the stringers. If possible, set your stair rise to 7-1/4 in. and tread to 11 in. (two 2x6s). Always leave a minimum of 3-1/2 in. of wood perpendicular to the back of the stringer and the deepest cutout.

Cut a stair stringer as you normally would, leaving it extra long on top. Cut an additional 1-1/2 in. off the top riser to allow for the rim joist. Then cut the stringer where it butts into the second joist (below).

Click image to enlarge.

Mark the stringer positions and nail 2x8 blocking between the joists beside those positions. Secure the stringers to the blocking with four 3-in. deck screws driven along the lower edge of the stringer.

5. Straighten a Bowed Deck Board
No matter how good your lumber supplier, a good share of your decking is sure to be bowed. Straightening bowed boards is a routine part of deck construction. The photos below show you how.

Set the board, bow in, and nail one end. Work toward the other end, nailing as you go. Drive a chisel into the joist and lever the board toward you. When the board is tight to your spacer, nail the board to the joist.

6. Trim Deck Boards Dead Straight
Beauty is in the details. Using a board to guide your saw as you trim your decking leaves an edge crisper than the steadiest hand can make. Set your guide board up as shown. If you use a 2x2 like we did, sight down it from one end to make sure you get it perfectly straight. You’ll have to cut the last two boards off freehand. Mark the entire cut with a chalk line and keep your saw going in a straight, steady motion.

Screw a straight board to the decking as a guide for your circular saw. Measure the distance from the edge of the saw blade to the base plate and position the board to allow about a 1-in. overhang for the decking. Run your saw along the edge, keeping the saw plate parallel to the decking and tight to the guide.

7. Craft a Beveled Post Cap
Placing a cap over your rail posts not only looks good but also protects the vulnerable end grain of the post from the weather. Caps for 6x6s usually must be special-ordered, but you can make your own from 2x10 material and save the wait and money. This jig is made from 16-in. pieces of 2x8 framing and 1/2-in. plywood (see illustration). Setting the plywood guide on the jig to your circular saw requires some trial and error. Adjust it so the blade leaves a slight reveal on the top of the cap. Secure the cap to the posts with construction adhesive and 3-in. galvanized finish nails.

Set the jig fence by clamping a scrap 2x10 (1-1/2 in. x 9-1/4 in. x 9-1/4 in.) to the outer support of the jig. Set your circular saw to a 15-degree angle. Run your saw through the jig. Adjust the fence so your saw blade just cuts through the top of the cap. Set the square 2x10 cap material in the jig and cut the bevel on all four sides. Sand the caps to remove any saw marks.