hardwood floor underlayment

[JD]

I have two quotes on putting down a hardwood floor in my home. One installer says that heavy duty poly sheet is best, another showed his underlayment and it looks like roofing paper to me. The floor would be installed over 3/4 plywood over a crawlspace. We will be using a 3/4 prefinished hardwood floor. What are the opinions out there regarding underlayment? Thanks JD

[Oren]

I'm thinking troll. Did you sell the townhouse you didn't or cannot fix for lack of $$$?

Is this the current single home or the townhouse?

Oren "My doctor says I have a malformed public-duty gland and a natural deficiency in moral fiber, and that I am therefore excused from saving Universes."

[JD]

I am not sure what you mean. It is my current home and we are upgrading from carpet to hardwood. We will be in the house another 10-15 years. One of the installers uses a product called AquaBar, which appears to be a sandwich of paper with a tar like substance in the middle. The argument he makes is that poly will leave holes but this aquabar paper seals around the staples. It makes sense to me on the surface, but I am still looking for advice. JD

[RicodJour]

AquaBar seems to be a laminated kraft paper/building felt (tar paper) product.

Regular 15# asphalt-impregnated building felt is what I put under hardwood floors. Some people use red rosin paper, but I like the vapor barrier qualities of the felt. AquaBar is essentially more expensive building felt. I'd choose that over polyethylene. I'd choose building felt over AquaBar and ask for a discount.

Frankly, the sealing around the staples is gilding the lily. The amount of moisture that would be introduced thorugh the staple holes is insignificant. If moisture through the staple holes is a problem, then you don't solve it at the floor underlayment level, you solve it down in the crawlspace with a barrier placed on the soil/cement and/or ventilating the crawlspace. Otherwise you're essentially saying, "I don't mind if the floor joists and subfloor rot, as long as my hardwood floor looks good." That's crazy talk!

R

[JD]

[Kevin Ricks]

I put plain old roofing paper under my HW floor (3/4" prefinished). Can't remember if I used #15 or #30. The roofing paper has better sound deadening properties IMO.

I did another floor with the floating laminate click lock type stuff and used the blue poly sheets as recomended by the manufacture.

Kevin