Repairing Decks and Railings
Easy fixes for common deck problems like rotten boards, wobbly railings and loose nails. Plus, see how to stiffen a bouncy, wobbly deck.
Replace broken deck boards
You don't have to let a split, rotted or otherwise ugly deck board ruin the appearance of your deck. Simply replace it and in a year or so the replacement will blend right in.
1. Cut out the bad board
You usually don't have to replace an entire board in deck repair work. Just make sure to cut out a piece that spans at least three joists. The remainder should be at least that long. And don't hesitate to cut out a little extra to keep adjacent decking joints staggered for better appearance. The most difficult part of this deck repair task is cutting out the damaged section cleanly. Don't try to cut directly over a joist. Instead, cut to one side and screw on a cleat to support the new decking. It's a fairly hefty cut for a jigsaw, so use a sharp, stiff blade to keep your cuts as straight and smooth as possible. Draw a square line on the decking to one side of a joist below. Cut the deck board with a jigsaw. Pull the decking nails with a cat's paw.
2. Add cleats to support the new board
Predrill three clearance holes in two 16-in. treated wood cleats so they pull tight to the joists. Also, pull up on them so they butt tightly against the decking on each side as you screw them in. Apply construction adhesive, hold each cleat tight to neighboring deck boards, and screw one to the joists at each end of the deck repair.
3. Install the new board
Cut the new deck board from matching material, both in thickness and wood type. It'll look different initially, but it'll blend in after a year or so, especially if you clean and reseal or stain your deck. Cut the replacement board to length (you want a snug fit). Then tap it into place with a hammer and a wood block. Predrill pilot holes and drive a pair of 2-1/2-in. deck screws (or galvanized nails) into each cleat. Fasten at all other joists as well for the deck repair.
Strengthen wobbly posts
You don't have to live with loose, wobbly railing posts when a couple of bolts will make them safe and solid. Measure the thickness of the post/framing assembly, add 1 in. and buy 1/2-in. diameter galvanized carriage bolts that length (plus a nut and washer for each) from any hardware store or home center.
1. Drill bolt holes
Drill the 1/2-in. clearance holes well apart, one about 1-1/2 in. from the top of the framing and one about 1-1/2 in. up from the bottom of the post. You may have to angle the holes slightly to avoid joists, framing anchors or other obstructions. If your drill bit isn't long enough to go through the post and framing, get a long spade bit. Versions up to 16 in. long are available at home centers and hardware stores.
2. Drive in the carriage bolts
Tap in 1/2-in. carriage bolts, shim if necessary to plumb the post, and install washers and nuts. Tighten the nuts until the bolt heads are set flush to the post. Most posts are held fairly plumb by the railing, but check them anyway with a level and tap in shims to straighten them if necessary. Don't over-tighten the bolts; the heads will sink deep into soft wood without much effort.
Stiffen a bouncy deck
A deck that bounces when you walk across it won't feel strong and solid, even if it meets structural requirements. The cause is usually long joist spans between beams or between a beam and the house.
1. Tap in snug-fitting blocks
To stiffen a deck, you have to be able to get to the framing underneath. You can add another beam, along with posts, to support the joists. However, this is a big job. We recommend that you first add rows of solid blocking every 3 to 4 ft. along the span (as demonstrated in this photo). Run the first row down the middle of the span, check the deck for bounce, then add rows to further reduce it.
2. Nail blocks in place
Use treated lumber blocking that's the same size as the joists (usually 2x8 or 2x10). Install the blocking in rows along a chalk line snapped at a right angle to the joists. You'll have to measure and cut each block separately to get a snug fit, since the joists are never exactly the same distance apart. Staggering the blocking in a step pattern allows you to easily drive nails from both sides, rather than having to toenail. Square each block to the joist and drive three 16d galvanized box nails through the joists into each end of the block. Repeat for each row.
Replace loose, popped nails
Decking swells and shrinks as it goes through repeated cycles of wet and dry seasons. This frequently causes nails to loosen and pop up above the deck boards. You can drive them down again, but chances are that's only a short-term solution. They'll probably pop up again after a few years. The long-term solution is to remove the popped nails and replace them with deck screws.
1. Start with a diagonal cutter
Grab slightly protruding nails directly under the head with a diagonal cutter. Roll the cutter back onto thin blocking to pry the nail up slightly.
2. Yank the nail with cat's paw
Tap the claw of a cat's paw under the nail head and lever the nail up. Finish pulling with a hammer or pry bar. Protect the deck board with a shim or thin block.
Take out the sway with an angle brace
Some otherwise solid decks tend to sway or wobble as you walk across them, especially decks resting on tall posts 4 or more feet above the ground. Angle-bracing the posts is one good solution to this problem, but the braces often look tacky. Instead, install an angle brace underneath your deck. It's a virtually invisible fix that all but eliminates sway. Cut and nail a treated 2x4 diagonally from corner to corner under your deck. Drive two 16d galvanized nails at each joist. If your longest 2x4 doesn't span the entire distance, don't worry. Add a second one starting from the other corner and run it back alongside the first, nailing it to at least two of the same joists. Have a helper hold the 2x4 in place while you drive the first nails. Driving 16d galvanized nails upward will give your hammer arm a workout! Thinking of building an all new deck? Here is a great collection of tips from a pro.
Originally Published:January 07, 2018