0 Helpful?

Polyethylene quality and characteristics

Hi. I have come across various qualities of polyethylene for use under my slab. The prices vary considerably; from ~$120 to $280 for 10 mil 20'x100'. I have been told that thickness being equal, some brands will degrade in a very short period of time (matter of years), as well as off-gas significantly more. They claim that the type that is "agricultural/construction film" are cheap and not intended for under slab use. Is there truth to this, and should I shell out 65-75% more money for the "better" grade plastic? Thanks in advance.

Asked by Matthew Michaud
Posted May 14, 2014 1:11 PM ET
Edited May 14, 2014 1:51 PM ET

Tags:

2 Answers

Select your preferred way to display the comments and click "Save settings" to activate your changes.
1.

Matthew,
As far as I know, the main reason that polyethylene degrades is UV exposure (sunlight).

Keep the polyethylene in the shade. Once it is covered with concrete, it should be fine. I have used 6 mil poly for the purpose, and I sleep well at night.

Answered by Martin Holladay, GBA Advisor
Posted May 14, 2014 1:55 PM ET
Edited May 14, 2014 2:15 PM ET.

2.

I have used boat shrink wrap which is darn good stuff just because I had some. I also laid generic black 6 mil on wet dirt in a crawlspace twenty years ago, was on it just this last month crawling about and it is like the day I installed it.

Answered by aj builder, Upstate NY Zone 6a
Posted May 15, 2014 11:34 AM ET

Other Questions in General questions

Concerns about backdraft and make up air

In General questions | Asked by Forum User | Sep 3, 15

Is this a risky wall assembly?

In Energy efficiency and durability | Asked by Jeremy Coenen | Sep 3, 15

Vented attic vs. a sealed, non-vented, airtight attic

In Energy efficiency and durability | Asked by Calvin Smith | Sep 1, 15

Penetrations in exterior foam and rainscreen

In Green building techniques | Asked by Brian Otten | Sep 3, 15
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!