Installing Natural Reflections on plywood subfloor over 42" crawlspace which is fully lined with 16 mil pond liner sealed to top of stem walls. Bruce says "Must use Vapor Lock underlayment." Questions.

Is a vapor retardant underlayment necessary with well-lined crawlspace?
What is Vapor Lock anyway - is it just plain sheet polyethylene or a thin polyethylene foam sheet?
How does it compare to asphaltic roofing paper?

If a vapor retarder is a better choice than rosin paper, it seems that the poly product would be better to have outgassing into one's home than an asphaltic product. Opinions?

Remofool,
Polyethylene is a vapor barrier used underneath the sub floor to retard transmission from the ground into the sub-floor and the finish flooring. Asphalt paper is a vapor retardant used over the sub floor and under the finish floor to retard vapor transmission from spills and surface moisture; it also act as a sound insulator. They have different purposes and are not interchangeable. The asphalt paper once covered will not emit significant amounts of gas into the room. Standard household cleaning product emits more harmful chemicals than asphalt paper covered by wood. If you are concerned about the installation of asphalt paper in your home the only other option you have is rosin paper in place of it. It is inferior to asphalt in vapor retardation and sound insulation.

What about Vapor-Lock? It's definitely what Bruce calls out to be installed on top of the subfloor. It doesn't look like asphalt felt in the photos.

It's not. I used it once years ago when Natural Reflections first came out. It looked like ordinary white polyethylene to me with the Bruce logo on it. I think you will be fine no matter which product you use under that floor because you are stopping the moisture before it gets to the subfloor, which is the correct thing to do. But to be on the safe side, warranty wise, it's best to follow the manufacturer's instructions.

Bruce has a different installation requirement that others, as most all manufacturers do. They only call for poly paper or their product to be installed over the plywood. As well they say the use of asphalt paper is optional. Which it is, but from experience without a layer of asphalt paper over the surface the floor will tend to create more noise than a floor that has it installed. In Bruce’s installation instructions under the heading “sub-flooring regiments must be:” it explains the optional use of asphalt paper. Personally, I use the poly, then plywood and finally asphalt paper on the top as a slip sheet and a noise barrier. Before I proceed with any installation of a new manufacturer's product I email them and get confirmation that my procedure will be covered under warranty. If you decide to use this technique then I would suggest doing the same. I know others use the poly and then the asphalt on top of the sub-floor which is normal install procedures for Bruce (Bruce does not warranty sub-flooring) but moisture in the sub floor, which will get in to it if the bottom is left exposed, will tend to weaken it over time. Personally, I try to always install asphalt paper as my slip sheet. It gives the floor a completely different feel.

To be on the safe side, I would poke the subfloor with a wood moisture meter and see what it reads. I would then poke about 3 different flooring boards to see what they read. Since Natural Reflections is a wide plank(at least what I've seen of it) You don't want them to be any more then 2% of each other, flooring and subfloor.

I believe Bruce's Natural Reflections is a 5/16" x 2&1/4" STRIP floor, not a wide plank.

http://www.bruce.com/resflram/na/bruce/ ... neId=191.0

Well, I didn't want asphalt inside my living space, so I went with 3' wide rolls of 4 mil polyethylene for vapor barrier, and rolled out rosin paper over that for a clean and quiet underlayment that's stiff enough to not rumple or slip. It's working ok. I'll skip the poly for the second floor.

Got the first 20 rows of Bruce 5/16" x 2-1/4 strip stapled down today. And yes, tavern-grade liquidation-sale Natural Reflections really is a second-class product. But it's not completely hopeless and it's miles ahead of 20-year old builder-grade pet-anointed carpet!! And only 939.75 square feet to go!

Thanks y'all.

This is an old thread I am resurrecting, but I felt like commenting for anyone else contemplating this.

I am doing a nail down of engineered floor on the 2nd floor of my house. I noticed the odor with the asphalt paper as I worked with it and once I got the subfloor tuned/flattened with with some 30# pieces and layed 15# over everything else, I realized I can't suffer to have this stuff in my home. While I know that once I get the planks down the smell will be gone, I also know that this crap will be outgasing low levels of miscellaneous hydrocarbons to the inside of my home for years. This is where I sleep.

I am not a freak about this kind of stuff--I believe in better living through modern chemistry, but why even go there and put this stuff in your living space when there are apparently alternatives? For example Lowes sells a felt underlayment, with a moisture barrier, its pricy, but seems to be equivalent to 30# without being soaked with asphalt. A lot of materials outgass, but why go with something that clearly has a lot of vapor to give off over time.

Since I am on the 2nd floor above a finished ceiling, I don't think I need any kind of vapor barrier so I could probably just buy felt off the role at the local textiles shop.

I have always received great advice here--my floating installation would not have been successful without this board. In this case I have already torn up the tar paper and I am resolved not to use it except for some small spots where leveling the floor got technical.

My advice, for any DIY, if the outgassing is any concern at all to you, just figure out an alternative. The might be trickier on grade, but like I said, why even put this crap in your home?

David

It's really nothing more than your roof. You can google a pdf of roofing felt off gassing
pretty easy. Beware of the attic. Seriously you will not even smell it after it's installed.

Just wondering how you installed the first rows without that awful adhesive.

Thanks for the reply.

If its in my home, all the vapor will outgas into my living space and circulate there. I have two layers of 30# felt on top of my roof. For vapors to get into my living space, it would have to permeate the MDF roof panels to get into the attic and then seep into the living space through the finished ceiling--pretty much impossible given the tendency will be for natural outdoor air currents to carry any vapors way..

I agree that vapor would be in such low concentrations, it would not be noticeable, but it would still be there releasing into my living space for years--there is no where else for it to go. That just seems like a bad idea to me.

As for the first rows, I have to start the floor into manufactured grooves on the landing of my custom staircase. So I am fabricating the first row of planks to have double tongues, one into the landing and the other to build the nail down from.

Thanks,

David