We are finishing our basement and installing engineered hardwood throughout (5" Armstrong Hartco Maple click lock flooring). We are putting down Dri-Core subflooring which is 3/4" OSB 2X2 panels on top of a hard plastic raised backing that serves to block moisture, and remove the OSB from the damp concrete. My question is, do we need anything else, other than the foam underlayment for the flooring? Should we put down plastic sheeting under the Dri-Core, or is that overkill that's not necessary?

Thanks for any suggestions!

I would run 6 mil poly under the Dri-Core, and run it up the wall a few inches. It's inexpensive, and the extra protection is smart. Plus running up the walls is a good idea, especially outside walls in a basement. Not familiar with Dri-Core. Sounds like a modular product. In which case I would assume the seams would need to be taped for an impervious membrane. Either way...it doesnt sound like a product that will roll up the walls for protection.

The walls will be fully covered in plastic. We can do the floor as easily I suppose. The Dri-Core is 2X2 tongue and groove OSB squares: http://www.homedepot.com/h_d1/N-5yc1vZ1 ... ogId=10053

Thanks for the link.

They state that the product allows for an "ideal foundation" for hardwood flooring. they also state it "allows the concrete to breath".

This is not a moisture vapor barrier. Manufacturer's require moisture vapor barriers on this type of installation.

Armstrong, as most manufacturers, have installations specs to follow for their individual products. I would go over their requirements. It wouldn't even hurt to give their tech dept a call concerning this Dri-Core, and follow what they specify. But as I stated, you will need a vapor barrier. Infact in this situation I would probably install 2 layers, if not a trowell on product like Bostik MVP4.

Actually, it is a moisture barrier. That's the entire point of it. It allows the concrete to breath while shielding the flooring from moisture via the plastic backing. It also does not recommend covering the floor in plastic. It gets rave reviews on every site I've seen.

Better check that warranty Holly and see what they will do to replace. I've read about it and I wouldn't trust it. Heard about a similar product failure.

I just reviewed the detailed installation specs and warranty and I have to say they are typical of a box store product, very vague. First of all the installation requirements states:

The Detailed Installation Guide

Preparation
1.The concrete floor and foundation should be relatively dry and free of large cracks, excessive moisture penetration flooding problems prior to installing DRIcore Subfloor panels. DRIcore is not meant to be a replacement for good foundation maintenance. Any moisture issues including leaks, excessive moisture, mold/musty spots, foundation cracks, window leaks, exterior drainage or hydrostatic pressure issues, should be resolved prior to DRIcore’s installation to avoid potential contamination to the finished project and surrounding building materials


See where it says "excessive moisture penetration"without values and yet again, "excessive moisture"? What do they mean by that? There should be specific numbers/values. Plus the warranty is iffy. And also you need to leave a 1/8 inch gap above the flooring to ventilate.

So it says "should be resolved prior to DRIcore’s installation to avoid potential contamination to the finished project and surrounding building materials". And how does one do that? First by doing moisture tests and then using a vapor retarder under it!!!

I see this as a boon to the inspection community.

Their covering their butt. No numbers. Scary thought in a basement, of all places. They specify solving moisture transmission before using their product.

Common sense....."It allows the concrete to breath". Do you really want to install hardwood in a basement over a product that allows the concrete to breath and emit moisture vapor into your hardwood?

Call Armstrong, Do they recognize this product as a vapor barrier?

It allows the concrete to breath underneath the vapor barrier because the plastic feet keep the product elevated off the concrete. Everyone I know loves this product so I was hoping someone here had experience with it.

I'm a little confused....You and "everyone you know" obviously sound sold on this product. Yet your posting whether to "lay down plastic sheeting". Then you post Dri-Core states not to lay plastic on concrete before Dri-Core. It sounds like you know more than most people about this product, which is great. Why the question? To me the wise decision would be to call Armstrong as I suggested numerous times, I get the impression you dont need to, again After all Armstrong is the manufacturer of warranty. If they say go for it....perfect.

I hadn't found on their website the note about not using plastic when I posted the question. And given how popular the product is, I figured someone here would have experience with it.

Holly, not everyones installation is the same, the house is not built the same, the dainage is not the same and the basement slab is not poured the same.

If I were you I would do as Floorologist says and call Armstrong, then call the manufacturer and ask them what they mean by excessive moisture and how to go about figuring that out.

My bet is they will not give you a direct answer. Then if you could get back to us. Sounds intriguing.

Yes, please let us know.

I would be real interested to know what they prefer people to do when they state not to use plastic, and they also state in the same breath to resolve excessive moisture before installation.
They do state solving the different problems that have created excessive moisture, leaks, etc. But you can still have excessive moisture in the slab presently, and from time to time, due to conditions aside from leaks etc. Also, down the road, depending on the problem, a plastic vapor barrier can save your floor untill an excessive moisture problem, a leak or such is solved if possible, since they are concerned about excessive moisture.

I'm just foggy on what they suggest you do to limit ongoing moisture. Whatever they define as "excessive".

I'll check with them (eventually LOL...work sucks right now and we won't be installing until probably January). But I think the best solution (to follow their installation directions and get additional 'insurance') would be to put vapor barrier on TOP of the dricore, and under the foam underlayment.

No I wouldn't do that. An OSB sammich does not sound very appetizing.