How to Patch a Porch Floor

This Old House general contractor Tom Silva eliminates a tripping hazard by replacing a broken board.

Step 1

Pull the Nails

These square-edged deck boards were face-nailed to the joists. To remove a board, Tom looks for a telltale row of nailheads, then uses a cat’s paw to pry out each nail in the board. If a nail is missing a head, he uses nail-pulling pliers, as shown.

Tip: When a nail must come out and saving the surface of the wood isn’t a priority, grab a cat’s paw. Place its claws next to the doomed fastener at a 45-degree angle and hammer the head into the wood until the claws straddle the nail shaft. If they don’t grab, place the cylindrical knuckle over the nailhead, whack the tool with a hammer to create a recess, and try again. Then rock the handle. That leaves the nail no choice but to back out.

Step 2

Remove the Broken Board

With the nails gone, Tom jams a pry bar under the break, levers up one end of the board, and pulls it out. He does the same at the other end. Scoring the paint along the joint on the board’s edges eases removal.

Step 3

Make the Cleats

To support the ends of the new board, Tom cuts a pair of cleats out of the cracked board, making each three times longer than its width. He squeezes construction adhesive on the ends of the unpainted face, as shown.

Step 4

Install the Cleats

Tom snugs a cleat, adhesive side up, under the neighboring boards and drills pilot holes through the deck and into it. He secures it with stainless-steel trim-head screws, as shown. The cleat at the opposite end goes in the same way.

Step 5

Cut and Fasten the New Board

Tom uses clear Douglas fir because it’s more stable and holds paint better than a cheaper wood. He cuts a single board to length, beds it in adhesive at each joist and cleat, and secures it at those locations with two hot-dip-galvanized 8d nails, placed 1/2-inch from the edges.

Step 6

Set the Nailheads

Using a nailset, Tom taps the nailheads a hair below the board’s surface. They’ll be invisible after the wood gets a coat of oil-based exterior primer and two coats of deck paint.