Hardwood floor underlayment

Hi,

I'm working on prep for putting in hardwood floor in most of the first floor of my house, which is fairly open floor plan.  This includes the kitchen, livingroom, and flex space between that can be dining room/kitchen/living room.

We will be using a strand woven bamboo, tongue and groove, nailed down.  The house was built in 1988 with a subfloor of 5/8" plywood over 16" joists, the flooring will be perpindicular to the joists.  There is a full basement underneath that is finished and climate controlled.  We live in PA so we have a varied climate. 

What is the right underlayment to use?  I've seen everything from 15lb roofing felt to fancy multi layer underlayments that are quite pricey.  What is the right answer? 

POR15 let cure for 48 hours then lay her down. 

Talk to the guys at Lumber Liquidators, they really knew their stuff when I went with a full-floating hardwood floor.  

Nailed down flooring usually just gets simple paper.  It's red and comes in great big rolls 3' wide.  

In reply to Sonic :

Pink building felt!  Don’t use tar paper, several issues with it.  The e pensive under-layments don’t really do anything special Although they charge  enough that you’d think they do.  

I used 15# roof felt, but red rosin paper is commonly used too.

Great to hear it is that simple, and that the cheap option works well.  Thanks. 

I've put down red rosin paper under the floors in 5 rooms in 3 different houses. Not sure if it is even necessary since it is not a vapor barrier, but it is cheap and easy to put down.

captdownshift said:

POR15 let cure for 48 hours then lay her down. 

Just be sure not to get it on your hootus.

In reply to T.J. :

Yes you need rosin paper.  Wood shrinks and swells depending on where the humidity is at the rosin paper allows the wood to move smoothly as it shrinks and swells 

tar paper doesn’t allow that smooth movement and will eventually loosen the boards as it fights the  stickyness.  

Tar paper also stinks. No tar paper!

I used the expensive spongey stuff in my house, and the red paper in my SIL's house. The paper made the flooring a lot easier to install. The boards slid nicely into place on paper, and didnt want to slide on the foam.