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Getting ready to install hardwood...what is best under it?

Posted by kbncan (My Page) on
Thu, May 24, 12 at 1:35

Hello, we have ordered 3/4" solid prefinished white oak hardwood floor. Our subfloor is 3/4" OSB glued and screwed to 16" floor joists above our basement which is heated. During the lengthy construction period of our home the subfloor had raised at some joints from rain exposure till the roof got put on. We will be sanding the joints as best we can but what should we consider for underlay of the hardwood?

I have heard just a " paper" more or less to help with install to slide better. Also I have seen more like a cushy foam that I think seems good for imperfections as well as noise reduction maybe. Anyone else seen or used this type of underlay for hardwood?

FYI moisture in the home is low as we have been doing the interior finishing for 1 1/2 years.

Follow-Up Postings:

RE: Getting ready to install hardwood...what is best under it?

We have engineered hardwood but I believe the same cork underlay would work in your case. It offers a 5/16 inch thick layer to cushion the floor and cover irregularities. Ours came in rectangles about 2'X3'. I think it came from You could check out that site. For the floor in my old house I ring nailed 1/4" plywood and put tar paper under it. Then had Armstrong designer Solarian layed. The underlay from Armstrong was a masonite type product.

RE: Getting ready to install hardwood...what is best under it?

Get it as smooth as you can with the sanding. I don't think you can use a pad under 3/4" flooring. Your best bet is get it as flat as you can and put a plywood rated for underlayment on top of that. Underlayment plywood has no voids to give or flex like Luan or reguar 1/4" plywood will. You can put a paper or even roofing felt under it.
I think the proper installation of that wood will be either nail or glue. If you glue, you shouldn't use anything but the underlayment under the wood. Glue wouldn't stick.
Your best bet would be go to the manufacturer's website and look for installation instructions or help. If you can't find that, try to get a number.
Flooring manufacturers look for any reason to dishonor a claim for adjustment. One thing done wrong and even if it has nothing to do with the defect, and they will usually disallow the claim.
I laid floors for @ 15 years, but have been retired for 5 and I have never bought a floor because I made sure to do everything the way they said. When I didn't agree with them, I got pictures and kept them.
You can't go wrong doing what they say...just keep records that you did it their way.

RE: Getting ready to install hardwood...what is best under it?

Thanks cer2010,
Wow I read the warranty fine fine print and pretty much NOTHING will be covered! It looks like a company's "Cover Their A$$" warranty. Almost anything could easily be blamed by us and our build.
I will document everything and be thorough and organized and maybe that will help if anything were to happen.

RE: Getting ready to install hardwood...what is best under it?


Need to ask some questions.
Are you going to nail this down yourself?
Is your flooring solid 3/4" White Oak or is it engineered White Oak flooring?
How wide is the flooring?
Where is the flooring currently stored?
Is your flooring a standard tongue and groove or does it have a kind of snap together system?
Are the ends grooved to fit to the next piece?
What is the range of random lengths on average?
How large is the area you will be flooring?
If necessary, could you add another layer of subflooring or underlayment to the OSB?
Have you done any remodeling or carpentry work before?
Do you have, or can you borrow, a moisture meter?

RE: Getting ready to install hardwood...what is best under it?

"Wow I read the warranty fine fine print and pretty much NOTHING will be covered!"

And even then, many of the warranties are limited to replacing the defective material.

You are left with removal of the old and installation of the new.

It is like a dog 'warranty' offered by breeders.

If the dog turns out to have a hereditary defect, you can return it when the defect is found.

Do you want to give up your dog?
Say after a few years?

RE: Getting ready to install hardwood...what is best under it?

My favorite is their policy of up to 10% defective per box... So I asked "Can I get away with paying 90% of the bill if I can only use 90% of the hardwood you delivered?" They didn't laugh.

We put down 3/4 natural Brazilian Cherry over the black paper (tar doesn't sound right but it is like that and was recommended) over the 3/4 plywood and had no issues. However, I quit reading their paperwork after 8.2% of the wood was defective and I couldn't return any! I had two full boxes of defective pre-finished wood.

Good luck. It was really fun using the flooring nail gun!

RE: Getting ready to install hardwood...what is best under it?

Randalls: Yes we are going to install (nail down ourselves).
It is solid 3/4" hardwood.
It is 3" wide I think.
DH just picked up all the boxes yesterday and place them all over the house in the rooms they will be installed.
It is standard tongue and groove.
Yes the ends fit in the net piece.
The lengths seem to range from about 18" to a little over 36".
We are covering about 2000 ft2 of main floor.
At this point (all walls in and cabinetry install etc...) we will not be installing another subfloor on top. We did for our tiled areas (bathrooms).
We (more like my husband) is very handy and has the tools. We have done this whole build ourselves.
I don't think we have a moisture meter. We live in western Canada so moisture is pretty low here. We installed by recommendation a steam type humidifier for the house (not operating yet) for all the wood floors and cabinetry.

RE: Getting ready to install hardwood...what is best under it?

Well we have begun the install of our hardwood! It is looking great. The sanding of our subfloor joints is going better than I thought it would. We ended up just putting a paper (Aquabar is the name) down then the wood. So far so good. I have just finished staining the heat registers to match.

RE: Getting ready to install hardwood...what is best under it?

Generally just a rosin paper (grey or red) is all that is used and its main function is to help eliminate squeaks in the flooring. Over 3/4" subfloor using another 3/4" solid wood flooring an additional layer of underlayment has never beed necessary as long as the subfloor is sound and the joints smooth and flat,

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