If You Can Access the Floor From Below
Put on eye protection to keep dust out of your eyes, and stand downstairs, while you ask someone to walk on the floor above. Listen for the squeak. When it occurs, watch to see if raised boards are flexing slightly down against the floor joists when the other person walks on them.
Mark where the boards are raised from the floor joists with chalk or a pencil.
Spread carpenter's glue on a thin wooden shingle or shim and tap it between the floor joist and the floorboards with a hammer. Choose a shim that's thin enough so it just fills the gap but doesn't raise the floorboards.
If You Need to Work From Above
Remove any area rugs, and walk over the bare floorboards until you find the exact location of the squeak. Look for one or more floorboards that depress slightly and squeak when you step on them.
Using a stud finder, find where those floorboards cross the floor joists.
Drill a pilot hole for a screw through the floorboard and into the joist. Enlarge the hole at the top with a bit that's as large as the diameter of the screw head, so you can sink the head of the screw 1/8 inch below the surface of the floorboard. Drill a similar hole into floor joists wherever you find a raised board that squeaks.
Screw flat head screws into the holes while someone stands on the floorboards, so the screws hold the floorboards down tightly. Use 2 1/2-inch screws, or ones that are long enough to go an inch into the joist below, depending on how thick your flooring is.
Using a putty knife, fill the holes above the heads of the screws with wood filler. Choose putty that's colored close to the color of the floor. With a barely damp rag or paper towel, wipe off any excess before it dries. If you prefer, sand the area around the repair, and finish it to match the rest of the floor.
Things You Will Need
- Chalk or pencil
- Wood shim
- Carpenter's glue
- Stud finder
- 2 1/2-inch flat head screws
- Wood filler
- Putty knife
- Rag or paper towel
- If you notice a cracked or weakened floor joist when examining the floor from below, a shim won't necessarily fix the squeak, since the floor joist itself may be moving each time someone walks on the floor. You'll need to strengthen the floor joist by attaching a sister joist alongside it or by adding a post to reinforce it.
- If you examine the floor from below and don't notice any gap between the floor and the top of a floor joist, check the surface of the floor from above and look for an individual floorboard that's raised and squeaking against its neighbor when you step on it. Fix it by screwing it down as described.
- Substitute nails for screws by nailing two into each joist at an angle and sinking the heads with a nail punch.