Three Ways to Repair Creaking Stairs

If you cannot get underneath, take up any carpet and firmly screw the front of the tread to the top of the riser.  Make sure that stairs are well lit and that any carpeting is securely laid so that no one can trip over it.

Gluing a Riser

Push a screwdriver between the tread and the riser and insert a piece of cardboard covered with wood glue.  Leave it there.  Repeat until the squeak is gone.

Adding a Wood Block

A persistent squeak may need tackling from under the stairs.  Glue a triangular block of wood into the corner of the tread and riser.  Secure it with screws.

Replacing Wedges

With old stairs, you may have to replace the stair wedges to fix a squeak.  Clean off the old glue, reapply, then hammer the new wedges back into place.