Vapor barrier under lift base....

[jtbinvalrico]

Work continues on my flush-mount lift install: https://www.garagejournal.com/forum/showthread.php?t=383717

Pits have been dug to 27". That's 14" for the lift platforms, 4" for compacted crushed stone, and a 9" concrete base. Walls are 5".

I estimate I'll need about 120 square feet of vapor barrier in the pits. The garage slab is about 2 years old. I found a vapor barrier under the slab when I cut the pits out. This is Florida, near Tampa, 1/2 mile from the bay.

I need some guidance on which vapor barrier to use. Searching has indicated much love for Stegowrap. Search results have also leaned toward much bigger projects....I don't mind spending the money for a good product, I just don't need such a large amount. Also, is "crawl space vapor barrier" an appropriate application here?

These pits are recessed into the floor, and as such the vapor barrier will see little to no foot traffic during the build. I understand one concern is folks walking on the vapor barrier and punching holes in it. Another issue is compatibility. Makes sense that using just any old sheet plastic may not be a good idea because it might degrade over time.

Then there's sizes. Seems like 6 mil might be too thin. Then there's 10, 12, and 15 mil options. Here's some of what I found on the net, in amounts that fit my project. Please have a look and critique as needed. Thanks!

https://www.kofflersales.com/p/craw...MIwden_fvo3QIVC4NpCh1cCAe8EAkYByABEgLNcfD_BwE

https://www.amazon.com/dp/B071CZPZBH/?tag=atomicindus08-20

https://www.amazon.com/dp/B0026KZCXC/?tag=atomicindus08-20

 

[brownbagg]

any vapor barrier will work, the thicker the better. and there are some high dollar vapor barriers out there. But any will work

 

[JamesW84]

for that small, I probably wouldn't worry about buying a super duper vapor barrier. You can do more than one layer without problems, so I read, so you could get a thinner 6 mil and layer 3 pieces (since you likely will have plenty).

I'm reseaching for my slab and I'm going with either Stego 15 mil ($460/roll 1960 sq ft) or Viper Vaporcheck II 15 mil ($255/roll 1960 sq ft)

 

[Leaflessshadetree]

I prefer 10mil over 2 layers of 6mil and it usually isn't expensive or difficult to find.

 

[ConCretin]

I'd probably just match what is there. It's probably 6 or 10 mil poly? No sense upgrading for the area under the lift. Just tape all the seams and you'll be fine.