There is one stair in my house that announces every late night trip to the kitchen. I lived with it for two years because I assumed fixing it meant pulling up the tread.

Where the Squeak Comes From

Wood rubs against wood, or against a nail. As the house settles and the air dries out in winter, the joint loosens and you get movement. The sound is friction, and friction needs two surfaces touching. Separate them or lock them together and it stops.

From Below, If You Can Get There

If there is a basement or an open ceiling underneath, this is the easy route.

1. Have someone walk the stair slowly while you listen from below.
2. Once you find it, drive a wood shim coated in wood glue into the gap between the tread and the stringer.
3. Or screw up through the tread into the riser with a trim head screw.

From Above, With No Access

Find the squeak, then work a little graphite powder or talc into the joint with a thin blade. It lubricates the surfaces so they slide instead of catching. That is temporary but it is quiet. A longer lasting option is a squeeze of construction adhesive worked into the gap with a putty knife, wiped clean before it cures.

Mine turned out to be the tread rubbing the riser, not a loose nail. A shim from below and a screw through the back had it silent in about fifteen minutes. I should have done it the first week.