Which closed-cell foam insulation to choose?
Insular
| Posted in Energy Efficiency and Durability on
With all of the types (and dealers) of closed-cell foam out there, how do you choose?
Lapolla and BASF seem to be two of the options I have. Is either one safer, better, more Green??
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Moya,
My own advice: choose a local installer with a good reputation. Ask for references and do your research. The skill and reputation of the installer matter more than the type of foam used.
Icynene offers a high density (but open cell) foam that can meet a class 2 or 3 vapor retarder with R values ranging from 5 to 6 per inch. The environmental advantage of this product is that they use water as the blowing agent. Closed cell spray foams use HCFCs as blowing agents which are greenhouse gases.
Aloha Energy (a smaller regional foam manufacturer in NY/NE) also has a water-blown closed cell foam that's significantly lower permeance than the Icynene MD-R-200 2lb foam.
The Icynene product is ~3x more permeable than most other 2lb foam (including the Aloha product) but somewhat lower R/inch (~R5.2/inch compared to R6-7/inch) than other vendor's goods. That said, at 4" it's still a class-II vapor retarder, yet still offers better drying capacity at any R-value compared to other closed cell foam, making it a preferred product in some applications (such as the underside of roof decks where outward-drying capacity is essentially zero.)
The difference in greenhouse gas between HFC245fa (the most commonly used blowing agent for closed cell foam) and water blown foam is more than 1000/1. That's a significant green-factor when looking at any thickness over 1.5-2".
http://www.aloha-energy.com/index.php
http://www.icynene.com/residential/products/md-r-200/specs
It's my hope that other vendors will get into the water-blown high-density foam game for it's dramatically higher green factor. Any foam that uses HFC blowing agents (and this includes all XPS rigid foam manufactured in the US) is the opposite of green when used for substantial insulation rather than for air sealing. The lifecycle impact of water blown foam (and the CO2 blown XPS used in Europe) is far more benign, and more likely to be net-positive for the environment, even in the near term.
Dana, thanks for joining this site. The informstion you provide is useful to many of us and much needed.
I fully agree with your post and Martin's.
I pulled the spec sheet on the Lapolla foam, which claims to be using
"...EPA approved next generation blowing agent...", type unspecified:
BASF is touting:
"...ZONE3® zero-ozone-depleting blowing agent technology..."
While HFC blowing agents (such as HFC134a and HFC245fa) are much less damaging to the ozone layer then the the previously use CHFC blowing agents,(notably HCFC141b) they are still g'dawful powerful greenhouse gases. But there are new classes of blowing agents being developed to address the GHG issue, some of which are even less damaging than pentane which does less than 1% the damage of the HFCs, but still ~7x that of CO2. (Pentane is often used for blowing EPS and polyisocyanurate in factory settings, but probably isn't adaptable for any foams blown in the field.)
Without more info on the actual blowing agents used by BASF and Lapolla it's tough to give a comparative answer, but the good news is that neither are likely to be the more damaging than the commonly used HFC245fa.
It's tough to beat water as a blowing agent for polyurethane foam. When using water blown SPF, the "payback period" on greenhouse gas damage paid in reduced energy use is on par with rock wool fiber insulation- a handful of years even at R50+ insulation levels, only modestly worse than (pentane-blown) EPS, but still ~10x that of cellulose.
See:
http://www2.buildinggreen.com/blogs/avoiding-global-warming-impact-insulation
The good news is that I'll be using a relatively small amount--2 inch over 800 sq feet. Maybe I'll add more when water blown is readily available.
Any thoughts on Bayer? I can't find much info on them on line/
Where are you located, and what is the application?
Midstate NY (Hudson region). Application is vented attic floor (6" joists), unconditioned basement ceiling and vented crawl space ceiling.
It's next to impossible to adequately air-seal the ceiling of a basement or crawl space, even with copious amounts of closed cell foam. Insulating and air sealing the foundation walls has proven to be more effective & reliable. You may want to review this before proceeding:
http://www.buildingscience.com/documents/reports/rr-1108-hybrid-foundations-retrofits-measure-guideline
Mind you, no matter what the R-value of the center-cavity fill you'll never exceed an average of ~R18 with 6" joists due to the thermal bridging of the joists, unless you encapsulate the bottom edges of the joists too. (With 2" between the joists the ~R2 of bridging joists yields an average R value of less than R10.) It's usually less material and more effective to insulate the crawlspace walls. With a full basement the volumes may be comparable, but even 2" on the walls is more effective than 6" between the joists.
Aloha Energy is in Saratoga Springs (http://www.aloha-energy.com/installers.html ) I'm sure they can recommend an installer local to you for their water blown 1.8lb spray polyurethane. (Reviews from local customers in VT have been pretty positive- good news for a small local manufacturer. Ask for references.)