There it is again - a loud squeak every time someone walks down the hall. This may be a good sound for parents hearing their kids coming home before curfew, but it's really annoying at 3 a.m. when someones just making a trip to the kitchen.
Floor squeaks are caused by natural shrinkage of wood due to changes in moisture content. As the wood dries, it shrinks, and nails can loosen. When you step on the ﬂoor, the wood moves and rubs against the fasteners. Squeak!
Many options exist to correct floor squeaks. Often you can work from below to add (or “sister") strips of framing wood to the existing joist. Use construction adhesive and screws to secure the strip of framing to the joist and the subﬂoor. The construction adhesive is the key - it bonds to all surfaces and will not shrink as it cures.
You can also add a thin wood shim to gaps between the floor joists and the subﬂoor. Again, use construction adhesive. Gently tap the shims into the gap. Don't pound the shims into the gap because this may widen it and make the problem worse.