Re-nail loose wood siding
A loose wood siding board has usually pulled away because its nails rusted, backed out or missed the studs. Nailing it back with galvanized or stainless siding nails into the studs, placed so they don't pin two boards together, holds it for good. Check for rot first; a soft board or a wet wall behind it is a different job. Right nails, right place, and the board stays put.
How wood siding is attached
Lap siding is horizontal boards that overlap like shingles, each covering the top of the board below so rain runs off. Each board is nailed into the wall studs, usually every 16 inches, with one nail per stud placed just above the top edge of the board underneath. That lets each board swell and shrink on its own.
Boards loosen when plain steel nails rust away, when nails missed the studs and only caught sheathing, or when sun and rain cup and twist the wood. A board nailed through both itself and the board below can also crack as the two move against each other.
Why siding boards come loose
Plain steel nails corrode away.
Nails only held in sheathing.
Sun and rain twist the wood.
They crack as they move.
| You notice | Likely cause | Start at |
|---|---|---|
| Board pulling out at the bottom | Nails let go | Step 3 |
| Rust streaks under nail heads | Rusted nails | Step 3 |
| Board split along its length | Nailed through two boards | Step 5 |
| Soft or dark wood | Rot or a leak | Call a pro |
Let's fix it
- Check for rot and waterPress the board and the ones around it with a screwdriver. Wood that's soft or crumbly, dark stains running down from the board, or a damp wall behind it mean rot or a leak; nailing won't fix that. Also check whether the paint is old enough to contain lead before you scrape or sand anything.
- Find the studsLook for the rows of existing nail heads running up the wall; they mark the studs, usually 16 inches apart. A stud finder works on some siding. Mark each stud location along the loose board in pencil.
- Pull out the bad nailsPull rusted or bent nails that aren't holding with a flat bar or the hammer claw, putting a scrap of wood under it so you don't dent the siding. Leave nails that are tight.
- Nail the boardAt each stud, drive a siding nail through the loose board just above the top edge of the board below (usually 1 to 1 1/2 inches up from its bottom edge, depending on the overlap), so the nail goes through only one board. Drive it snug, so the head sits flush, not crushed into the wood. Predrill within 2 inches of the ends so they don't split.
- Fix a crackFor a split board, work exterior wood glue or epoxy into the crack, press it closed, and nail on each side of the crack into the stud. Wipe off the extra. A board that's split through its length or warped badly should be replaced.
- Seal and paintDab exterior caulk or primer over each nail head, and caulk any open joint at the board ends. Prime bare wood, then paint to match once it's dry. Paint is what keeps the wood from soaking up water and loosening again.
Watch it done
- The board sits tight against the one below
- No nail heads sticking out
- Heads are sealed and painted
If it's vinyl or the paint is peeling
If it's vinyl siding, see the guide for reattaching loose vinyl siding.
If the paint is peeling, see the guide for fixing peeling paint.
What a pro typically charges (a rough estimate; prices vary by area): A siding contractor or handyman typically charges $150–$400 to renail and patch a few boards, more for replacing rotted boards or working up high.
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Loose wood siding questions
How do I reattach loose wood siding?
Nail it into the studs with galvanized or stainless siding nails, just above the top edge of the board below, usually 1 to 1 1/2 inches up from the bottom edge.
What nails should I use for wood siding?
Hot-dipped galvanized or stainless steel siding nails. Plain steel nails rust and stain.
Where do you nail lap siding?
Into each stud, just above the top of the board below, so each nail goes through only one board.
Why is my wood siding coming loose?
Rusted nails, nails that missed the studs, or boards cupping from sun and rain.
Can I glue a cracked siding board?
Yes, with exterior wood glue or epoxy, then nail on both sides of the crack. Replace a board that's split through or rotted.