Floors that squeak when you walk on them can drive you crazy. But don't start pulling your hair out just yet--there's hope. Floors squeak because over time, wood dries out and shrinks, creating small gaps between boards. Eliminate that gap and you get rid of the squeak. Often you can fix your squeaky floor with one of these simple techniques.
Often you can't get to the underside of your floor to work on the squeak (the squeaky floor is on the second story or there is a finished ceiling below the squeak).
Eliminate small squeaks by sprinkling some talcum powder or powdered graphite (NOT liquid graphite lock lubricant) along the seams of the floorboards. (Graphite is messier to work with than talcum powder). Cover the powder with a paper towel or a cloth and step on the boards a few times to work the powder into the seam. Then vacuum up the residue.
The powder will often provide enough lubrication between the boards to stop them rubbing against each other.
Still squeaking--fasten the floorboards more securely to the sub floor.
Install 6d or 8d flooring nails at least 1/2 inch from the edge of the floorboard right down into the subfloor. Predrill holes slightly smaller then the nail shank to prevent the floorboards from splitting.
Sink the nail heads below the board surface and patch with wood filler color matched to your floorboards.
Alternatively you can use small screws to fasten the boards, since over time, screws hold better than nails. Countersink the screw heads below the floor surface and patch the hole with wood filler.
Check the cross bracing between your floor joists. If it's loose, reattach it--using screws.
Try putting shims on top of the floor joists directly under the floorboards. Push the shims in tightly but don't pound them in or you might actually push the floor up from below.
Alternatively, fasten your sub floor to the floor joists by installing extra screws driven at an angle through the floor joist up into the sub floor.
Another option is to install extra 1" x 4" bracing between floor joists. Screw the bracing firmly into the sub floor using screws just long enough to go through the sub floor, but not all the way through the floorboards themselves.
Roll back the carpet if possible, so you have direct access to the floorboards. Use one of the techniques suggested for working from above.
If you can't remove the carpet you can nail right through the carpet and the flooring directly into the sub floor.
Use a stud finder to find your floor joists then drive your nails into the underlying joists.
Putting a little construction adhesive on your screws or nails before installing them will help them hold over the long haul. If you're using screws, square head (Robertson) screws are the easiest to drive in. Enlist a helper to stand on the floor where you're installing any screws or nails. Their weight will push the floor closer to the underlying joists.
Never try to use screws when fastening through the carpet, the screw twisting its way through the carpet will get tangled up in the carpet fibers and make a mess.