Fix a loose deck stair tread that rocks or creaks
A deck stair tread that rocks or creaks is common, and it happens to most decks over time. Outdoor wood swells and shrinks with the weather, and smooth nails slowly work loose. A loose tread can tip under a foot, so fix it soon; often two deck screws per stringer solve it. If the tread is cracked or soft, you replace that one board. If the stringer itself is damaged, stop and call a pro.
How a deck stair holds together
Most deck stairs have two or three stringers. These are long boards, usually 2x12, with notches cut into the top edge like a saw blade. Each tread sits flat on a notch and is fastened down into it. The top of each stringer hangs from the deck framing, often with a metal hanger or bolts. When everything is tight, a tread doesn't move or make a sound when you step on it. Your weight passes from the tread into the stringers and down to the ground.
A tread loosens for the same reasons deck boards do. Wood swells when wet and shrinks when dry, and that movement slowly lifts smooth nails. Stair treads take hard, uneven loads from every step, which speeds it up. Once a nail lifts, the tread rocks and wears its hole bigger. Screws hold better because their threads bite into the stringer. The Treated Wood Council says to use hot-dip galvanized or stainless steel fasteners with pressure-treated wood. It also says to treat cut ends with a brush-on preservative, since the treatment may not reach the core.
Why a deck stair tread comes loose
Weather cycles lift smooth nails out of the stringer.
Each rock widens the hole, so the nail holds less.
A split board can't hold a fastener or carry weight.
Water sits on the tread and the end grain rots.
The support under the tread is failing. Call a pro.
The top connection has loosened. Call a pro.
| You notice | Likely cause | Start at |
|---|---|---|
| Not sure what's causing it | Close the stairs and probe the wood | Step 1 |
| Nail heads sticking up | Pull them over a scrap block | Step 2 |
| Need the right fastener | Pick screws rated for treated wood | Step 3 |
| Tread rocks, wood is firm | Drive two screws per stringer | Step 4 |
| Tread is cracked or soft | Pry it off and cut a new one | Step 5 |
| Railing moves or steps feel uneven | Check the rail and every tread | Step 6 |
Let's fix it
- Close the stairs and probe the woodPut tape or a rope across the top and bottom of the stairs. Then find out what you're fixing. Step on each tread with one foot while holding the rail. Note which ones rock, creak or flex. Press the tip of a flathead screwdriver into each loose tread, near the ends and the nosing. Firm wood resists and only dents. If the tip sinks in or the wood crumbles, the tread is rotting; go to Step 5. Now look under the stairs at the stringers, mainly near the ground and at the top. Probe them the same way. If a stringer is soft or cracked, or it has pulled away from the deck, stop here. Keep the stairs closed and call a deck builder. If everything is firm, go to Step 2.
- Pull the popped nails over a scrap blockPut on safety glasses and gloves. If a nail head sits above the wood, slip the claw of a hammer under it. If the head is flush, tap a cat's paw under it with short hammer strokes. Lay a scrap block of wood beside the nail and rest the tool on it. The block spreads the force so you don't crush the tread. Rock the handle back slowly. Switch to a taller block as the nail rises, so it comes straight out. Keep your face out of line with the nail. If you only need the stairs usable today, you can drive a raised head back below the surface with a nail set instead. Expect it to rise again. If a head snaps off, set the stub below the wood and screw beside it.
- Pick screws rated for treated lumberMeasure a pulled nail. Buy exterior deck screws long enough to pass through the tread and reach well into the stringer. For a 5/4 tread, about 1 inch thick, 2 1/2 inch screws are a common choice. For a 2x tread, about 1 1/2 inches thick, 3 inch screws are typical. Check what your deck is made of. Pressure-treated wood can corrode plain steel. The Treated Wood Council recommends hot-dip galvanized fasteners or stainless steel for treated wood. Near salt water or a pool, choose stainless. Many coated deck screws are also rated for treated lumber and say so on the box. If the box doesn't say, pick another one. Don't use drywall screws; they are brittle and rust outside. For composite treads, use the screws the maker names.
- Drive two screws into each stringerFind the stringers under the tread. The old nail rows show where they are. Mark two spots over each stringer, about 1 inch in from the front and back edges of the tread. A spot about 1/2 inch beside an old hole bites fresh wood. Near the end of a tread, pre-drill first, because a screw there can split the board. Use a bit slightly thinner than the screw's shank. Wear safety glasses. Stand on the tread to press it down, then drive each screw straight with a drill or impact driver. Stop when the head sits flush. Don't sink it deep, which crushes the wood and holds water. Step on the tread again. It should feel solid and quiet.
- Replace a cracked or soft treadWear safety glasses and gloves. Back out any screws. Pull the nails with a cat's paw over a scrap block, or tap a flat pry bar under the tread and lift it in small moves at each stringer. Measure the old tread's length, width and thickness. Buy matching lumber, often 5/4 decking or a 2x6, in the same material. Keep the same thickness, so each step stays the same height. Cut it to length and match the front overhang of the other treads. If the old tread was two boards, leave the same small gap between them. Brush a wood preservative on the cut ends. Then fasten it as in Step 4. If the stringer notch under it is soft, stop and call a pro.
- Check the handrail and every treadBefore you open the stairs, walk them slowly, up and down, holding the rail. Every tread should feel solid and quiet. Lay a level on each tread front to back. It should sit level or slope very slightly forward to shed water. Look at the steps from the side. Each rise should look the same height. Building codes such as the IRC generally limit how much one step's height can differ from the next to 3/8 inch, because an odd step trips people. Grab the handrail and shake it. If it moves, tighten it before you open the stairs. Our guide to fixing a wobbly deck railing shows how. If the whole stair still flexes, call a deck builder. When everything is firm, take down the tape.
Watch it done
- Each tread feels solid and quiet underfoot
- No nail or screw head sticks up
- Every step looks the same height
- The handrail doesn't move when you shake it
Still rocking? Probe the stringer under it; a soft stringer won't hold any screw.
If it comes back
If a tread loosens again, the screw may have hit soft wood or missed the stringer. Probe the stringer near that spot. Our hammer guide covers pulling nails without denting the wood.
If the deck boards above have the same problem, see fixing popped deck nails or replacing a deck board. Sealing slows the swelling that loosens fasteners; see cleaning and sealing a wood deck.
If the railing moves, fixing a wobbly deck railing walks through it. Stairs that sway or stringers that pull away from the deck need a deck builder.
What a pro typically charges (a rough estimate; prices vary by area): A handyman typically charges about $100–$300 to refasten or replace a few treads. Rebuilding stringers costs more and needs a deck builder.
Find a deck builder near you