With the carpet off, pry up the treads
Squeaky stairs are easy to fix from underneath—provided they’re exposed. A simple fix is to tap shims into voids between the treads and the stringers and add some glue. Then screw the stringer to each stud. But most stairs are finished on the underside with drywall or plaster. Squeaks in these stairs need to be fixed from the top. That’s why the perfect time to fix them is when you’re replacing the carpeting—you can remove the treads and get at the squeaky culprits. (If you’re not replacing the carpet, but you have a squeak that’s driving you nuts, see below for how to fix tread squeaks right through the carpeting.) Here are four easy steps to permanently fix the treads that squeak and keep the rest from ever starting.
After you’ve removed the carpet, use a flat bar to pry off the treads, working from the top down (Photo 1). Since you’ll be reusing the treads, remove the nails and any leftover carpet pad and staples. Screw the outside stringers to each stud with 4-1/2-in. screws (Photo 2). Starting with the bottom tread, apply a bead of subfloor adhesive along the top of the riser, the stringers and the back of the tread, and press the tread back into place. Next, drive three 2-1/2-in. screws through the top of the same tread into each stringer (Photo 3). Then, drive a 2-in. screw through the riser into the back of the tread between the stringers (Photo 4). Repeat these steps with each tread, working your way to the top of the stairs.
Note: Your stairs will be out of commission for a couple of hours, so let everyone in the house know what’s going on. Make sure you cordon off the top to keep someone from tumbling down the steps while you’re working!
Fix Squeaks Through Carpet
If you have carpeted stairs and a squeaky step that's driving you crazy, you can still fix it without removing the carpet. Check the internet or home centers for special kits that tighten treads without damaging the finished floor. The kit shown here is designed to send a snap-off screw right through the carpet without damaging the fibers. Find the squeak by bouncing up and down on each step, then drive the specially scored screw through the middle of the depth control jig, down through the carpeted tread, and into the stringer or riser nearest the squeak. The jig stops the screw head right below the tread's surface. Use the screw gripper located on one side of the jig to rock the screw back and forth until the excess length snaps off.