Hello and thanks, in advance from a first time poster.

I'm planning to install about 550 sq. ft of 3/4' prefinished solid oak over a circa 1974 5/8" subfloor in a living / dining room adjacent to a kitchen on a second floor over a sleeping area below. Reducing footfall below is a priority but I already own the material, so floating / glue down engineered options are out. The kitchen finished floor level sits a full 1 1/2" above the subfloor after resheeting / decoupling / soundproofing and installing the travertine. It is desirable to have all meet in the middle so the easiest approach would be to be to green glue and screw about 20 sheets of 3/4" ply or OSB to the subfloor, then nail away. 3/4" + 3/4" makes 1 1/2.

The problem is that green glue only goes so far and I'm wondering about footfall in particular. Some options I'm considering:

a) 5/8" ply or OSB over green glue then Quietwalk under the naildown
b) Same as above only floormuffler
c) A cork sandwich with green glue jelly

Any thoughts / insights will be very much appreciated

Dave:

Define this green glue/jelly. I'm having problems getting around this.
You would need something firm if you're trying to achieve the same vertical height as the travertine and what's under it.

I think the cork option is the best, but once fasteners are used you lose some of the benefit, unless the fasteners used do not penetrate the actual sub floor. In that case 1 1/2" flooring nails or staples.

There are other sound deadening products out there. Hopefully others can contribute.

Ken:

Thanks for the reply. The "green glue jelly" was just my irreverent description of making a "sandwich" with green glue viscoelastic caulk between substrates. It has some sound reduction properties as the sound waves get interupted by the caulk layer. It does not help much with footfall, hence my dilemma.

Which soundproofing will yield better IIC results... 1/8" cork or 1/8" Quietwalk, assuming I still use the 5/8" ply on top? How deep into the underlayment will 1 1/2" nails penetrate? I get that the nails transmit sound. I'm just trying to minimize at this point given the givens.

Thanks & regards,

My opinion on the matter.

I think all those under layments are a marketing scheme... There are so many types at high costs and honestly not needed. What ever happened to the good ol' hardwood floor right on top of sub-floor with some felt paper between? I've installed many "real" wood floors and that's all we ever used.

The cork, gel and vapor barriers, do they do anything other than make a floating floor gushy and soft? I am sorry but walking on a floor that moves a millimeter is not my kind of floor.

I would suggest to save the cost, buy some 3/4 OSD Tung and groove and whatever else it will take to build up the sub-floor to match.

Unless its designed for a smooth transition from one room to the other, a small step down probably won't be too bad.

Also your probably better off insulting the floor from the basement, then putting your sound deadening material on the ceiling... but that's of course its open and you can get to it.

You'll get more noise coming from subfloor and joists than foot steps on the floor. Won't do much good to take extreme measures on the floor unless your joists and subfloor are perfectly sound too.

Just my thoughts on the matter.