This is a follow up question to this old thread: Replacing hardwood floor in 100 year old house with no subfloor The house has hardwood floors installed directly on floor joists and the floors are very squeaky.
Since the floors are opened now as part of a larger remodel, I wanted to take the opportunity to address squeaking. To the extent that squeaking is caused by the extra flex in the boards in between the joists, below is a proposal to brace the floors by installing "subfloor" in between joists. My question is if I should use a binder layer between existing flooring and the subfloor that will be installed - the layer that is shown in blue. I was talking to one flooring person, and he said "No" since the blue binder would "prevent floor from moving". This seems counterintuitive since in the typical modern installation, subfloor is nailed to the floor joists and then the tongue and grove flooring layer is nailed to the subfloor, thus all layers are connected together transitively through nailing. It seems that the blue "binder" layer in the Proposed solution would be similar.
Since my floors are opened now, I can do a test to see if the Proposed solution addresses the squeaking and see it for myself. My only concern is around long-term implications that may not be apparent on Day 1. Such as, if binder layer does in fact prevent the necessary movement, this may take a season change to manifest itself, etc.
Which binder layer do you think best addresses squeaking and has no long-term negatives?
- Construction Glue
- Some type of caulk/glue that has some flex to it when is dry to allow for movement.
- Foam/rubber/some type of underlayment pushed up against the bottom of subfloor, but not glued.
- Nothing. Don't do it, because....