under slab poly size

[Ohmthis]

I'm getting ready to pour the slab on my shop. What size poly would you recommend?

 

[dfiler2]

Enough to fit the size of your shop?

Assuming you mean the thickness, 6-mil poly will satisfy most codes, 10-mil or thicker vapor barriers designed specifically for use under slabs are less likely to puncture or deteriorate.

 

[chamoisfive]

I guess you mean the thickness required, therefore you need to check with your local authority to see if they have a particular thickness required. It will depend on your winter conditions of course.
The minimum here in temperate NZ a few years ago was a miserable 30mm, now it is mandated 50mm minimum. Personally, I believe the more the better but then I don't know what your budget is, or how you are with "doing things to the minimum standard required"

Edit: Oops. I thought you meant insulation poly(styrene)

 

[bigman68]

It will depend on what you are looking for and how much you want to spend, the best and most expensive is Stego Wrap or a similar material:

http://www.stegoindustries.com/products/stego-wrap-15-m-1.php

If cost is an issue go with 6 Mil or 10 Mil regular poly.

 

[willymakeit]

I personally like 10 mil. Use the correct tape on the seams and seal the edges to the footing if you can.
Google vapor barrier install. I deal with a lot of this on com. projects and the exterior, under slab envelope systems are becoming a big deal.

 

[brownbagg]

don't get the thin stuff and make sure your finisher don't clean their come along by banging on the plastic

 

[rburke65]

At least the 10 mil. Tread lightly on it!

 

[K'ledgeBldr]

As a general rule- 6mil
But have a read-

http://www.concreteconstruction.net/concrete-slabs-and-floors/better-garage-floors.aspx