Problem: Floors or stairs emit annoying squeaks when stepped on.
Background: Floor or stair squeaks are common in homes and are usually caused by floor components rubbing against each other. Squeaks can be caused by floor materials that have dried out and become loose or separated. They may also be caused by loose X-bridging between the joists, by gaps between the joists and sub flooring, or by plumbing pipes or ducts rubbing against the joists.
What to do: First try to pinpoint the area of the squeak and see if the problem can be fixed from below the floor or stairs. Check to see if the squeak may be caused by the X bridging lumber, which is used between the joists visible in the basement. You may be able to correct this by cutting away wood where the Xs cross with a handsaw. Check and readjust any loose pipes or pipe hangers in that area. If there is a gap between the joist and sub-flooring, try driving in wedge- shaped shims above the joist. The squeak may be caused by the separation of the sub floor and floorboards. In this case, try driving screws through the sub floor, into the boards above, to draw the two together. (Make sure the screws reach only about halfway into floorboards.) If this doesn’t work, try using concealed nailing from above, or lubricating the squeak area.
Special advice: Before driving nails through hardwood flooring, drill pilot holes that are slightly smaller than the nail size to avoid splitting. Start the pilot hole at the edge of the board and angle it down and toward the center of the board. When refastening stair treads to risers from the top side, drive flooring nails at an angle toward each other. In either case, you can use a nail set to avoid marring board surfaces, and wood putty to cover the nail holes.
Helpful hint: In some cases you may be able to stop the squeak by using powdered graphite, available at hardware or auto parts stores. Spray the graphite into visible cracks in the area of the squeak. This may lubricate the parts that are rubbing together and stop the noise. Another option is to reinforce the tread/riser joints with wooden blocks, using construction adhesive and wood screws.