Directors of classic horror films frequently used a squeaky stair sound bite to create a sense of fear and dread in the viewers psyche as the monster deposed its next victim. The slow, high pitched creak foreshadows the approach of something unknown, an impending doom.
While the squeaky stair in your house is surely nothing to fear, it can be annoying. There are rare occasions in which the squeaky stair is indicative of a larger structural problem, but most of the time it is a fairly simple thing to correct. Before tearing apart your staircase in a panic to find structural problems, try these simple solutions to see if you can restore the quiet to your flight of stairs.
A warped tread typically causes the squeak. The tread is the part of the stair onto which you actually step. As the tread dries over time, it either cups, or bows. If it cups, it forms a slight "U" shape. If it bows, it forms an upside down "U" shape. When that happens, the wood is pressed back towards its original shape every time someone steps on it.
As the wood is pressed back into a flat piece, it rubs slightly across the surface upon which it rests. The structural pieces on which the step rests are called stringers. When the wood from the tread rubs on the wood that makes up the stringer, then you have a squeak.
To determine the location of the squeak, try a simple experiment. Locate the tread that is the squeaky culprit and take a heavy step on the very edge. If doing that produces the squeak, then the problem is most likely a cupped tread. The solution is to fasten the tread to the stringer tightly, thus pulling the cup out of the tread.
By looking closely at the surface of the tread, you can locate the position of the stringer that supports it. Simply find the nail or screw holes where the tread was originally installed and plan to make your repairs on that same line. On staircases with finished wooden treads, it is advisable to pre-drill a small hole. Finished wooden treads are often made of oak and could easily split if not pre-drilled with a hole that is a slightly smaller size than the screw you are using.
You are trying to pull the "U" flat. Use a thin screw, #6 is a good diameter - with a fairly small head, so that you can countersink the screw and fill the hole with wood putty. Doing so will allow you to preserve the finished look of your staircase. In a situation where the tread is cupped, sink the screw at the very front and at the very back of the tread.
If during your experiment, the stair does not squeak when you step on the edge, but it does squeak when you step in the middle, then the tread is most likely bowed. The repair process is similar to fixing a cupped tread, only in this instance, the nail goes in the middle of the tread. The goal is the push the middle of the bow flat.
Fill the Gap
There are instances where these solutions are not enough to pull flat a tread that is very old, very hard, or very dry. In these cases, the squeak may actually be caused by the tread rocking back and forth when someone steps on it. There is no elasticity left in the wood that will allow it to be secured tightly to the stringer with a screw.
The best option in this case is to find the place where the gap between the tread and the stringer is the largest, and use a shim to fill that gap.
A shim is a small wedge of wood that is narrower at its tip than at its base. By sliding a shim into the gap until it is tight, you will eliminate the space that allows the tread to rock on the stringer.
Once the space is filled and the shim is tight, pre-drill a small hole. Sink the shim through the tread, into the stringer in order to tie all three pieces together. Use a coping saw to gently remove any excess pieces of the shim that may protruding.
These are simple solutions that will solve most squeaky stair problems. While there is no longer a guarantee that you will be able to hear the monsters as they the ascend the stairs, there will be the peace of mind that comes from eliminating unwanted structural noise from your home.