Fixing Squeaky Stairs and Floors

A squeaky step at 2 a.m. isn’t a structural emergency, but it’s maddening, and in an old house the fix is usually simple once you’ve found exactly what’s moving.

Why old wood squeaks

In older houses the floors and stairs were nailed together, often without glue. As the wood swells in humid summers it can pull nails up slightly; when it shrinks in dry winters, the nail is left a little loose. Step on it, and the board squeaks on the nail, or two boards squeak against each other ¹. Loosened joints, wear, and stairs built with too little glue add to it ¹.

Find the squeak

Walk up slowly, stopping on each step, and press different parts of each noisy tread ¹:

• Front of the tread: likely loose from the riser below it.
• Back of the tread: likely separated from a stringer.
• Sides: the side stringers or loose balusters.

If you can get under the stairs, have someone walk up while you listen and mark each noisy step ². Stairs usually have three stringers, one at each side and one in the middle; This Old House’s Tom Silva reads the nail patterns on the treads to locate them without crawling underneath ¹.

From below

If the underside of the stairs is open, from a basement stair or a closet, you can fix squeaks invisibly:

• Shims. Where there’s a gap between a tread and a stringer, squirt in glue and tap in a thin shim ^{3 1}.
• Glue blocks. Glue and screw triangular or square blocks into the corner where the front of each tread meets the top of the riser below, using screws short enough not to poke through ².
• Wedges. Traditional stairs often have housed stringers: each tread and riser sits in a slot cut into the stringer, locked by a glued wooden wedge driven in from underneath. When wedges work loose, chisel them out, reglue them, or cut new hardwood wedges and knock them home. Fit the riser’s vertical wedge first and trim it before driving the tread wedge ².

From above

When the underside is plastered over, work from the top ³:

• Angled nails. Tighten a tread to its stringer by driving two finish nails at opposite 45-degree angles, so they act like a clamp ¹. Set the heads and fill.
• Screws and adhesive. If you’re replacing carpet, pull the treads, clean off nails and staples, and reinstall each tread on subfloor adhesive with screws into each stringer and a screw through the riser into the back of the tread ³.
• Through carpet. Snap-off screw kits drive a scored screw through the carpet into the stringer, then break the head off below the surface ³.

Before you screw or nail, shim any gap on top of the stringer, as Silva does, so you aren’t just pulling the tread down into a void ¹.

Floors

Floors squeak for the same reasons, usually where the subfloor has lifted off a joist. From the basement, have a helper walk above while you mark the noisy spots on the joists. Tap a glued thin shim into the gap between the joist and the subfloor, gently, because overdriving it can raise the floor above, then drive a short screw at an angle through the joist and shim into the subfloor ⁴. Hardware brackets that pull the subfloor down tight to the joist work too ⁴. On carpeted floors with no access from below, a breakaway-screw kit is the tidy fix ⁴.

Try it

Pick your worst step. Stand on it and rock heel to toe: is the noise at the front or the back? Then look underneath if you can. One glued shim or glue block may be all it takes.