I am installing 3/4" solid oak with nail-down installation into 5/8" plywood subfloor over 16" on center floor joists on the upper level of a split level house.

I was recommended to purchase the GenieMat RST 05 product [1] by a contractor based on concerns I had with impact noise that can be heard on the lower level.

I have a couple questions around the assembly here. The current plan is:

5/8" subfloor
15 lb asphalt saturated roofing felt
rubber underlayment (GenieMat RST)
finish floor
L-cleats through the finish floor to the subfloor

The manufacturer recommends against this method because sound transmits through the cleats and thus they don't want to support - however I'm told in practice it's done similarly to this because the 5-10% reduction in performance isn't worth the alternatives. Alternatives being changing the flooring type or adding another layer of plywood above the rubber underlayment, gluing that and the rubber down, and then nailing the finish floor through the new plywood.

Given that this is the case, I'm wondering whether I need to increase the thickness of the subfloor before getting started. I believe I found one installation recommendation that the subfloor should be 1" thick, but I've looked into other rubber underlayments that don't make the same claim.

Thanks for any feedback or recommendations.

[1] http://pliteq.com/products/geniemat-rst.php