Sales guy at a supply house changed my mind about moisture barriers

I always thought the cheap 6 mil poly was good enough for any concrete slab. Been doing it that way for like 8 years. Then a sales rep at Dalton Flooring Center showed me a test where moisture vapor came right through two layers of the cheap stuff in under 24 hours. He had a little demo setup with a cup of water and a piece of glass on top. That visual made me actually buy the proper vapor retarder with the higher perm rating. Has anyone else seen those moisture meter readings go crazy even after using standard poly?

2 comments

2 Comments

laura_knight542d ago

That little cup demo is wild because it makes you realize how much moisture is actually moving through the ground. What thickness and perm rating did you end up going with on that vapor retarder? I've seen guys swear by 15 mil but then others say 10 mil is plenty if the seams are taped right.

the_kim1d ago

Buddy of mine went with 10 mil on his shop build and taped every seam like his life depended on it. Bone dry three years later, so I'd say that's plenty if you do the work right.