How to Fix Squeaky Floors: From Above, From Below and Under Carpet

Floor squeaks typically come from seasonal wood movement, a loose nail, or a gap between the subfloor and the joists. The fix you need depends on two questions: where is the noise coming from, and can you get underneath the floor?

This guide covers why floors squeak, how to pin down the exact spot, and the main repair methods for each situation: working from a basement or crawl space, working from above on hardwood, and dealing with squeaks under carpet, tile and laminate.

Why floors squeak

Flooring guides agree on a short list of causes.

  • Seasonal movement. Wood swells when the air is humid and shrinks when it is dry. The American Hardwood Information Center says most squeaks come from this normal cycle of expansion and contraction, which makes boards rub against each other.
  • Loose fasteners. That same movement can work nails loose over time, so a board slides up and down a nail shank every time someone steps on it. This Old House notes that swelling can push a nail up slightly and leave it raised once the wood dries.
  • Gaps between subfloor and joists. As the wooden subfloor dries and shrinks or buckles, it can pull away from the joists that support it. When you step on that spot, the subfloor flexes down into the gap and back up again, and the movement makes noise.
  • Installation shortcuts. Too few fasteners, the wrong type of nail, or a subfloor that was never properly fixed to the joists can all leave room for movement. BuildDirect points out that some newer homes have subfloors fastened with nail guns rather than screws.

Knowing which of these is behind your squeak helps you choose the fix.

Step 1: Find the squeak

Do not start drilling until you know exactly where the noise is.

  1. Walk the floor slowly and listen.
  2. Mark each spot with painter's tape or chalk so you can find it again.
  3. Use a helper if you have a basement or crawl space. One person walks slowly overhead while the other watches and listens from below with a flashlight. Look for visible gaps or movement under weight.
  4. Notice whether the floor moves. This Old House says to look for visible gaps or movement under weight.

Step 2: Fixes from below

If the squeak is over an unfinished basement or crawl space, fixing it from underneath is often the neatest option because nothing shows on the finished floor.

Shim a small gap

Where there is a small gap between the top of a joist and the subfloor, a wood shim can fill it.

  • Coat the shim with carpenter's or wood glue.
  • Slide it into the gap until it is snug.
  • Do not force it. Bob Vila's guide warns that forcing a shim can widen the gap; if it is not quite snug, you may need more than one shim.
  • Leave the shims undisturbed for 24 hours, as Bob Vila's guide advises.

Bob Vila describes shims as suited to gaps of less than half an inch deep and about a foot long.

Fill a long, narrow gap with construction adhesive

For a narrow gap that runs along the joist, construction adhesive applied with a caulk gun can fill it. Bob Vila's guide describes forcing the adhesive into the gap, repeating on both sides of the joist until a bead bulges out along it, and staying off the floor above for at least a day while it cures (about 24 hours to fully cure). Follow the ventilation and protective-equipment directions on the adhesive's label; that guide recommends a respirator with an organic vapor cartridge.

Add blocking or a brace

When the gap is larger, or a section of subfloor does not sit squarely on its joist, add support rather than filling the gap.

  • Blocking: This Old House describes cutting a short block to fit between two joists, gluing it, pressing it up against the underside of the subfloor at the squeak, and fastening it into the joists with angled screws or nails.
  • Sister brace: Bob Vila describes cutting a 2x4 at least 2 feet longer than the creaky area, setting it in the corner where the subfloor and joist meet over a bead of construction adhesive, and screwing it in.

Screw the subfloor to the finished floor

If wood flooring sits on top of the subfloor, a short screw driven up from below can pull the two layers together. The key is length. BuildDirect says the screw should be barely longer than the thickness of the subfloor so it does not poke through the finished surface. Measure the subfloor thickness before you buy screws.

The American Hardwood Information Center describes a related method: apply construction adhesive where the joist meets the subfloor, then drive a screw at an angle through the side of the joist into, but not through, the subfloor, with someone standing on the spot above to keep the layers tight.

Step 3: Fixes from above on hardwood

If there is a finished ceiling below, or the squeak is on an upper floor, you will need to work from the top.

Try a dry lubricant first

The American Hardwood Information Center calls lubrication the easiest solution and lists powdered soapstone, talc or graphite between the boards. Cover the area with a cloth and step on it to work the powder in. One or two additional applications may be needed. The same guide notes that sometimes the squeak is in the subfloor rather than the floor boards.

Refasten the board with finishing nails

A loose board can be nailed down to the subfloor. Guidance from the American Hardwood Information Center:

  • Pre-drill a pilot hole to keep the wood from splitting.
  • Start it at least half an inch from the edge of the board and angle it slightly toward the center.
  • Press down on the board while you drive the nail, countersink the head, and fill the hole with matching wood filler.

BuildDirect suggests driving the nail at a 45-degree angle near a joint, then adding a second nail angled the other way so the two resist pulling out.

Use breakaway screws

Breakaway screw kits, such as the Counter-Snap system This Old House demonstrates, are designed for this job. A depth-control fixture sits on the floor, the screw is driven through the board into the subfloor, and the head snaps off at the fixture, leaving a small hole that is filled with a matching wax filler stick. Before using one, find out whether your floor sits on a subfloor or on sleepers, because that determines the screw length.

Squeaks under carpet, tile and laminate

Carpet. BuildDirect describes cutting a small slit in the carpet backing with a sharp utility knife, driving a screw through the subfloor into the joist, then working the carpet back over the screw head. Breakaway screw kits are also sold for carpeted floors; This Old House notes that the small holes disappear into the carpet fibers.

Tile. Tile leaves two options: fix it from below, or lift tiles and repair from above. BuildDirect calls lifting tile risky and recommends a professional unless you have tile installation experience.

Laminate. Laminate is designed to float, so it should not be nailed or screwed down. BuildDirect suggests removing the perimeter trim to check for a perimeter gap, then gently loosening the squeaking planks to allow more movement. If that fails, the underlayment may be the cause, and the planks may need to be unlocked so the subfloor under them can be secured before reinstalling the trim.

Keeping floors quiet

A few habits can help:

  • Keep indoor humidity steady. Both the American Hardwood Information Center and This Old House recommend this, since it reduces seasonal movement. A dehumidifier in a damp basement or crawl space can help.
  • Use rugs in busy areas. Area rugs in entryways and living areas cushion high-traffic spots.

When to call a professional

DIY fixes suit isolated squeaks. If the floor is tile and you do not have tile installation experience, BuildDirect recommends a professional. If you suspect structural damage, get professional advice.

Quick answers

What is the easiest way to stop a squeaky floor? The American Hardwood Information Center calls lubrication with powder the easiest fix for squeaks between boards; refastening the board with finishing nails is another option it describes.

Can I fix squeaky floors without going into the basement? Yes. Finishing nails and breakaway screws are driven from above, and BuildDirect describes a screw-through-carpet method for carpeted floors.

Will a squeak come back? It can. Wood keeps moving with the seasons, which is why steady humidity matters as much as the repair.

Bottom line

To fix squeaky floors, find the exact spot first, then match the fix to the cause: powder for boards rubbing together, shims, adhesive or blocking for gaps under the subfloor, and nails or breakaway screws when you can only reach the floor from above. Check screw lengths carefully and let glue cure for the time the guides give.

This article is general home-maintenance information. Follow the instructions supplied with any adhesive, fastener or repair kit, and get professional advice if you suspect structural damage.

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