How To Fix a Squeaky Stair

Squeaky wood stairs are caused by friction against the nail shanks. Because stairs get a lot of traffic, it is almost inevitable that nails will start to drop from the wood.

How Not to Fix Squeaky Stairs!
If you are familiar with the process of fixing squeaky floors, this is substantially the same. Maybe you already know that hammering down loose nails is only a temporary fix as the nail will soon be lose again - or worse, back out to where someone might get hurt. Hammering in a second nail, next to the squeaky nail is a little better, but not much. If you decide to go this route, be careful that the new nail doesn't split the tread - a very real possibility, especially with older homes and stairs.

Screw 'Em!
The best solution is to pre-drill a hole next to the squeaky nail and secure the board with a screw into the underlying riser.

If you have access directly to the tread (the stair treads are not covered with carpet), you can apply some caulking into the squeaky riser-tread joints or into any cracks. Caulk isn't glue, it serves as a kind of cushion letting the objects still move some.

To really do the job right, it helps if you have access to the underside of the stairs. The fix then is similar to the fix that you would take to fix a squeaky floor board. With this method, you can investigate and see if there are blocks that were attached to the joints between the risers and treads. It is possible the blocks have fallen out or broken. In this case, you reattach or replace the wooden block of with construction grade wood glue and finishing nails. Alternatively, beneath the stairs you may find wedges at the riser-tread joint. In this case you can lightly tap in new wedges to which you applied a light layer of construction grade wood glue.

That's all there is to it!