Moisture Barrier over Concrete Slab
We plan to install strandwoven click together solid bamboo floating floor over a moisture barrier on our ground floor concrete slab. The slab was installed in the 50s. It is not insulated and it does not have a plastic membrane or anything between it and the ground. We have not really had any moisture issues, but we need a moisture barrier for the warranty and want to play it safe.
We want to know if the moisture barrier fabrics that are used under tile would be a good choice. We would mud down the fabric and apply the wood on top with the required 1/16" or less pad between the fabric and the wood. We would follow the instructions for installing the tile moisture barrier, but not apply thinset and tile on top. Here are some the products we might consider:
NobleSeal TS, Thin-set waterproofing membrane; Dal-Seal TS (Dal-Tile Corp.); or the Schluter Kerdi or Ditra product.
We did investigate the plastic dimplemats. We tried a 1/2" thick dimplemat product by SuperSeal. It sounded like rice crispies when walking on it, although the dimplemat was sandwiched between garden cloth and the 1/16 foam floor pad. We will try the Superseal "warm and quiet" product next. However the bamboo requires the underlayment to be no more than 1/16" to prevent the click together floor from creaking or flexing. We'd probably have to put plywood on top of the Superseal dimplemat, which presents a height challenge.
Hence, we are hoping that the CPE tile isolation membrane will provide the moisture barrier we need without needing to add more height with an additional plywood layer.
Our flooring needs a vapor barrier with a perm rating of .13 or less for warranty. The Nobel has a perm rating of maximum 0.15 perms, but I'm not sure if I found the right specs. What I found was for steam room testing (ASTM E96/E96M, Procedure E uses the desiccant method at high temperature 100 deg F ). Kerdi has a perm of .75, according for the customer service, but I don't know what they were testing.
Any recommendations? Any thoughts?