Now here's a good picture of the
construction adhesive that has been applied to the stair stringers,
before attaching the treads. Put a liberal bead of construction adhesive
on each stringer.
Here's the best tip I could give you to reduce the chances of your
stairs actually squeaking, in the future. Applying more construction
adhesive to the center stair stringer than to the outside stair
This is the area where most of the stair squeaking is going to happen.
Think about it, rarely, if ever are you going to use the edges of the
stairs to walk up and down. Just a little food for thought.
Split Level Stair Framing