I need some advice from the pros on this one.

I have an existing 3/4" T&G oak hardwood floor that's on diagonal plank subfloor over the joists. The floor can't be refinished and will take some work to level out. I would like to install a 1/2" T&G engineered hardwood floor over top throughout the entire house (minus the bathroom). Due to the layout of the house, I'd like to keep the planks running in the same direction as the original floor. And I really do not want to demo the old floor!

1. I need help determining what type of install to do: floating or nail-down/glue-down? From what I have read, people seem to recommend the floating install so that there are no concerns with the new floor moving with the old floor. Conversely, I have also read that if you install 3/8" OSB over the hardwood and screw it to the joists, you are okay to attach parallel to the old flooring. Any thoughts?

2. I have read that floating floors sounds hollow. Is that true?

3. A highly recommended floorer who appears to do a great job is recommending I nail AND glue down OSB, then do a glue-down floor installation. He gave me an estimate to level the floor, do the OSB glue-down/nail-down, under-cut the kitchen tiles under the kitchen cabinets, and do a glue-down installation of 824 sq ft for $4250 with a 7-year warranty. I already have the flooring material. Does that sound reasonable?

Seems that doing the floating installation myself would be much simpler, but I want to do this the right way (short of demoing the old floor).

Thanks,

Chris

Don't run the floor the same way unless you overlay it and don't use OSB, is plywood really going to break ya enough to consider using a less quality underlayment on your investment? On an engineered half inch I doubt your going to hit much of the hardwood below with the fastener and OSB is not to be trusted. But at least yours will be be new OSB. I just don't trust it.

I'm probably mistaken, I think he will be using plywood, not OSB.

I don't think I understand the rest of your comment. What do you mean by 'overlay?' I'm guessing you mean don't attach directly to wood floor if running parallel. And you're saying fasteners (staples) won't hit the old flooring. Is that right?

What's your recommendation? Glue, nails? What do you think of the estimate I was given?

Nail and glue the plywood. But why glue a hardwood down? Does he not have a stapler for this engineered floor? That just makes a plank replacement very difficult. Price sounds to low but maybe thats just your area. Is he a licensed contractor or a handyman?

Who is warrantying the floor, the manufacturer is 7 years, but what about the installation/labor warranty?

I asked him about nailing/stapling and he said he wouldn't do that for 1/2" planks due to splitting of the tongue. I was leaning towards stapling and it sounds like this is appropriate for 1/2", so I don't understand that one. Seems like he really prefers glue.

He is a licensed general contractor, but specializes in hardwood. The manufacturer's warranty is 15 year wear/30 year structural. He is warrantying his installation for 7 years.

So you're recommending nailing/glueing of plywood and staple installation of flooring? What thickness of plywood? I'd like to keep it as thin as possible. Should I still do the 15# roofing felt/rosin paper on top of plywood?

Thanks!