Helpful? 0

"EPS is the dominant sub-slab insulation material in Europe". What is/are the source(s) for this statement? Dana Dorsett quote.

I am researching the use of EPS and XPS in sub-slab applications for standard residential housing. Thus far it appears as XPS is winning the battle here in the US but I hear that in Europe, EPS is the dominant product of choice. I would love to get some sources to confirm this and to find out "why" Europe ended up going towards EPS over XPS ... I have my suspicions but in data I trust!

Based on the data and research I have found (mostly from product manuf. and some independent studies), I have drawn the following conclusions:

+ XPS has much slower "uptake" of water based on ASTM C272 testing ... b/c its closed cell structure is uniform and has no "voids" like EPS.
+ EPS has much higher "release" of water based on ASTM C1512 testing ... b/c these "voids" are where the water is held versus in the closed cells. XPS is much slower to "release" b/c the water is trapped in the higher ratio of "broken closed cells". Anyone have independent sources here?
+ Due to this fact, both products are compromised regarding the R-value performance. However, over the long term, it would seem, XPS would likely continually (albeit slowly) degrade in R-value performance as compared to EPS. Unfortunately I can't seem to find any conclusive proof of this?
+ Per "lab testing" both products have "data" which the other can use against the other. However, long term, unbiased in-situ testing has yet to be done satisfactorily.

I believe it was Dana Dorsett who stated that "EPS is the dominant sub-slab insulation in Europe" but can he cite a source for this statement as well as some of the above statements?

Asked by Colby Swanson
Posted Wed, 04/02/2014 - 12:41


6 Answers

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This press release from ACH Foam Technologies purports to present data on this question. A big caveat: ACH Foam Technologies is a manufacturer of EPS.

Here is the link to the press release: ACH Foam Technologies Stages Foam Face Off.

Answered by Martin Holladay, GBA Advisor
Posted Wed, 04/02/2014 - 12:51

Helpful? 1

Let's call this the Battle of the Press Releases. Owens Corning, a manufacturer of XPS, has come out swinging with its own press release, Owens Corning Foam Insulation Compares Extruded Polystyrene (XPS) Versus Expanded Polystyrene (EPS).

Answered by Martin Holladay, GBA Advisor
Posted Wed, 04/02/2014 - 13:04
Edited Wed, 04/02/2014 - 13:04.

Helpful? 1

Anecdotal information on the use of rigid foam in Germany comes from GBA's intrepid European correspondent, Andrew Dey, who has reported in a GBA blog: "In the U.S., one can readily purchase different types of rigid foam in 4'x8' sheets. In Germany, on the other hand, EPS is by far the most common type of rigid insulation."

Answered by Martin Holladay, GBA Advisor
Posted Wed, 04/02/2014 - 13:09

Helpful? 0

Thanks Martin ... yes, this is a biased study. My primary goal is to find data supporting Dana Dorsett's assertion that "EPS is the dominant sub-slab insulation used in Europe" ... I am just looking for the source to back this up.

Ultimately I am trying to better understand why Europe leans towards EPS and the US leans towards XPS. My hunch is that the reason the US is leaning towards XPS is mostly b/c of better "advertising" and positioning.

What is a bit perplexing about this whole EPS/XPS debate is the following:
+ The differences in EPS and XPS product characteristics are pretty narrow ... yet the cost is significantly different. Favors EPS
+ The moisture discussion is totally biased towards which "test" the product manuf. use to produce their "performance data" ... yet the ultimate driver should be in-situ testing. Again, at this point in my research, EPS wins here too b/c it "releases" water faster which I deem to be more important for long term performance.
+ Long term R-value is dictated by the moisture performance and further in-situ testing is needed.
+ EPS is the clear winner when it comes to GWP and general sustainability.

Answered by Colby Swanson
Posted Wed, 04/02/2014 - 13:12

Helpful? 0

In Germany, BASF is the dominant manufacture of EPS (Styropor/Neopor) and also XPS (Styodur) so they would have a strong influence in that region (I know this b/c I used to work for BASF but in N. America).

However, in Scandinavia where they seem to be ahead of the "energy" curve regarding building practices, I think they also have chosen EPS over XPS but I can't prove yet.

Do you know of any EU based research entities that may have looked into the EPS/XPS question?

Answered by Colby Swanson
Posted Wed, 04/02/2014 - 13:17

Helpful? 0

My use of this rigid EPS or XPS like 2" thick sheets... is that XPS is a much better product.

But when going subslab and much thicker...for me I would go EPS feeling that very thick sheets aid EPS in the ways that thin sheets bug me.

NO science... just gut feelings and use. 2" XPS is sturdy.... it gets walked on tossed and more... with no issues.

Answered by aj builder, Upstate NY Zone 6a
Posted Wed, 04/02/2014 - 13:23

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