foam insulation

Peelin back the onion usually has the singular effect of makin me cry.

Bob, for me, someone who is not normally involved with commercial low-slope systems, but of whom a solid knowledge base is nevertheless expected, which insulation is more cost effective?

I want your answer, but can I change the subject just a bit for a moment? Here's a link I found this morning. What concerns me is the 39-yr. membrane spec (no. 3 on their list) for rubberized asphalt. ??? Any comments on that or the other membranes and membrane life expectancies they listed?

http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_03b5/0901b803803b58ce.pdf?filepath=styrofoam/pdfs/noreg/179-05281.pdf&fromPage=GetDoc

Mike, why are you 1000 miles away and why was the iso frozen in a solid block in Alabama with an assumed ambient temperature too high for that (?) and are you augmenting your crew with local tradesmen or importing the works?

Well it looks like the peelin back of the onion has begun. I would have to agree with everything Mike has said...and like I said....everything has its "place".

In a normal low slope roof configuration with steel deck, FM has ( or at least used to have) requirements specific to placing a thermal barrier between the deck and XPS, the top floor directly underneath the deck has to be sprinkled and you cannot recover over the original roof assembly that has the XPS in the assembly. There is a difference between UL Class A and FM Class 1A. UL does approve some XPS directly over steel deck without a thermal barrier being place first....and I seem to remember that a recover board is required. Without doing some digging, I can't remember if the testing criteria is based on UL 1256 or some other/newer testing criteria. Unless my info is outdated, FM does not recognize XPS directly over steel deck in a FM Class 1A assembly.

When considering water absorption in a normal low sloped roof situation.....if you're getting enough water leaking into the insulation layer/s....all the XPS in the world will not save the roof or solve the problem. I'm not attempting to sell for OR against anything here....just expressing my opinion. Again, everything has its place and in normal commercial roofing with steel decks, there are other Thermal assembly options that are more cost effective than XPS. If it is an FM insured building with steel roof deck, there is no doubt in which insulation is more cost effective.

Egg,

I'm not sure what you were seeking comment on, and if Bob was across the hall, I'd ask his opinion on the following, but alas, we are 1000 miles apart.

In my experience, XPS has at least one superior characteristic and that is the likely hood that it maintains it's r value throughout it's lifespan.

XPS, even in ponded IRMA configurations, seems to absorb a minimal amount of moisture. Comparing that to Expanded PS and ISO, which will soak up a significant water content... IE: a job in Alabama just completed where we were removing 4x8 sections of 6.5" iso that weighed in excess of 200# and were solid blocks of ice... the R-value of this stuff was zilch.

XPS has always been a tough sell due to cost. Iso is easy. Rarely does the roofing industry, and consumers, embrace a product that often requires more steps to install and more money to buy.

Egg.

I'm sure you remember how little I think of all this Green and LEED stuff and how I believe it is simply just more layers of Gov't HooPlah....and.... Yes.... I do have opinions on that particular article and will reserve my comments in this forum with exception to the following:

1. Note who authored the article and where they hailed from.

2. With all the acronyms (ie; ASTM, XPS, EPS, XPSA, UL, LEED) I am not surprised to see the lack of any reference to FM or FMG (Factory Mutual Global).

Actually, everything has its place and one needs to be able to peel back the onion to find relevancy.

Now....let's light up some Esoterica and proceed with peelin'!!!!!!! ;)

Search engines are still mind-blowing for me. Here's an interesting link: http://www.mces.com/phenolic%20report.htm

Here's one that doesn't reply specifically to this question but is just as interesting: http://www.rci-online.org/interface/2011-01-marvin-byrne.pdf

Appears that in 2008, some people... http://www.foamsales.com.au/information/phenolic-foam/

Can't keep up with all these corporations: http://articles.chicagotribune.com/1996-08-27/news/9608280305_1_tenneco-packaging-amoco-unit

Here's an interesting bit:http://www.mlmlaw.com/library/cases/environ/Amoco.htm

Bob P: Do you have any comments on this one? : http://www.roofingcontractor.com/articles/xps-design-considerations-for-extruded-polystyrene-roof-insulation

Years ago we did a shingle roof with insulation and a wood surface for the nailing. It was phenolic foam and it was made by Koppers. It was a light green and it sounds like what you are seeing. I don't know for sure.

not xps. felt facer on bottom side fiberglass facer on top.

Sounds like AMOCO Foam Products - extruded polystyrene