I'm installing BR-111 5/16 solid brazilian cherry over a pine floor. I have room to put a 3/4" subfloor useing OSB tonge and groove (ok or other suggestion). I am confused about BR-111's instructions with the vapor barrier they say (I think) to aply a min. 6 mill. poly film. This is not installed over concrete or is there a moisture problem. I am going to put down 15lb felt under the osb and on top of osb for squeaks. This is the layers ( joist , pinefloor , 15 felt , OSB tg , 15 felt , BR-111). Is this OK or do I need to put down the poly? I am stapling the floor. Any other suggestions that you have would be of great help?

BR-111 states in their 5/16, staple down, raised foundation section... "6 mil poly "must be established" over plywood or equivalent (OSB). Joints overlapped 18" and taped. 15 lb asphalt felt may be used in addition to the moisture barrier ".

I would do exactly that. Lay the poly over the OSB, and then the felt.

I've never thought that was a good idea to make impervious sandwiches out of wood material... but if they say do it, just keep that paper handy.

I always thought that way Jerry, but once the staples are used it is not impervious.

Puncture holes are created. Yes?

I agree with Jerry and Ken so I looked up the installation info on 5/16 exotic and if it is the same material it says it is for floating and glue down applications only and "Do not nail or staple this product". It also does not mention the 6 mil plastic as an underlay.

Here is the instructionshttp://www.br111.com/pdf/Engineeredinstall.pdf..

If this is the same product maybe a call to the company would be appropriate.

Thanks for Most of the help------------------ it is a solid floor not engineered

It's the pine flooring part that concerns me. I suggest you contact Br111 and spell out your plan as you did here and see what they say..... get it in writing too.

On the 5/16 solid staple down, the way I read it is they are talking about the poly over the top of the plywood or OSB, not underneath.

To me, if you were installing over a raised foundation, wood subfloor, over existing vinyl, it would be the same concept.

Ofcoarse it never hurts to call the tech. dept.

I use Aquabar paper for most on the nail down hardwood floors.
This is a great moisture barrier.