Hi all,

I had a slab poured in my backyard for a shed that I’m finishing.  I did not have have insight to have the concrete contractor put in a vapor barrier.

As I’ve been working on the inside over the past few months, I’ve notice that humidity is significantly higher than outside, so I’m thinking some type of vapor barrier prior to LVP flooring is a good idea for a number of reasons.

The 10×16 slab is ‘semi-floating’:  the outside 12″ perimeter has a 12″ deep footer, and the remainder of the slab is 6″ deep.  Since it’s installed on a slope, one side has 2″ exposed at the top, and the other 8″ exposed.  There is no chance for actual water entering from the sides:  the problem appears to be limited to vapor.

What do you folks believe is necessary to control humidity?  I would imagine there is little to no hydrostatic pressure.  And is radon a concern?

The options I’ve been weighing are Roll-Cote, RadonSeal, and simply 6mm poly (but I’m concerned about trapping moisture).

Thanks,
Steve Williams