My house is just 15 months old, but the hardwood stair treads have begun to squeak when stepped on. The squeaks seem to be coming from where the risers join the back of the treads. Can you give any advice on how to silence this problem?

— Stephen F. Scarpino, via email

Andy Engel: My guess is that the connection between the back of the treads and the front of the risers is failing and allowing them to move independently, so they rub together and squeak. To fix the problem, you’ll need access to the back of the stair, which probably means removing drywall. Once the back of the stair is accessible, open the tread/riser joint with a putty knife or a small prybar and squirt in some carpenter’s glue with a syringe (glue syringes are widely available online, but you can also use a basting syringe from a housewares store). Even better is to have a partner squirt in the glue from above as you hold the joint open from under the stair, making sure to be diligent when cleaning it off the finished surfaces. Next, drive screws—spaced every 8 in. or so—through the back of the riser into the tread. (Wear a hat when doing this to keep the glue out of your hair.) Use quality self-drilling screws, not drywall screws, which are too prone to breaking. If you find that you can’t open the joint and get some glue in, just screw it.

If it turns out that the problem is between the front of the tread and the top of the riser, glue and screw 1x wood blocks to the back of the tread/riser joint.

Another possibility, particularly if the stairs are site-built with traditional notched stringers, is that the stringers have dried and shrunk away from the treads. Again, you need to open up the back of the stairs. If there’s a gap between the tread and the stringer, squirt in glue until it drips, and then slide in shims until they fit tightly. Finish by checking the riser/tread joint as mentioned above, and add at least a few screws for good measure.

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