[Greenbuilding] [BULK] Re: Cellulose settling

Fri Jul 28 09:17:11 CDT 2006

Hi all,

  I've been following this thread, and I'm puzzled:  Why has no one suggested low density, open cell foam-in polyurethane eg Icynene?  Granted, it doesn't have the recycled material content of cellulose, but it's stability over the temperature range and air sealing qualities have made it really attractive to me and my office colleagues.  Icynene has a pour-in formulation for closed walls.  Here's what EBN has to say about Icynene:

  Icynene is a low-density, open-cell modified polyurethane that is typically foamed into open cavities. The product has a very high (100-fold) expansion rate, so installation involves spraying on a very thin layer—much like spray painting. Within seconds, the foam expands to its full thickness, filling (and often overfilling) the cavity. The cured foam has a density of about 0.5 lb/ft 3 (8 kg/m 3) and an R-value of 3.6 per inch (RSI/m-25). 

  About two years ago, Icynene introduced a slightly different formulation for use in closed cavities. In this formulation, the Icynene is poured into the cavity and expands from bottom to top to fill the cavity. The company recommends two pours: one to fill the cavity about 90% full, then a smaller amount of foam to top it off. The cavity-fill product has a slightly greater density and an insulating value of R-4/inch (RSI/m-28). 

  From an environmental standpoint, there are several advantages to Icynene. First and foremost is the absence of any ozone-depleting chemicals. Water serves as the foaming agent, reacting with the other components to generate CO 2, which expands the foam. (The switch by conventional polyurethane manufacturers from CFC-11 to HCFC-141b has greatly reduced the ozone-depletion impacts, but even the HCFC depletes ozone to some extent.) 

  Second, Icynene has a very low density, one-quarter that of conventional closed-cell polyurethane. As a result, less petroleum-based material is required in its manufacture. (Note, however, that the R-value is significantly lower than that of closed-cell polyurethane, so the difference in material use per insulating unit is less.) 

  Third, Icynene is very effective at sealing air leaks in buildings. In fact, the company has promoted the product as much for its air-sealing properties as for its insulating properties. As a polyurethane, it adheres extremely well to most surfaces, and because the foam remains flexible, it expands and contracts with seasonal movement of a building to remain airtight. 

  Fourth, testing indicates that Icynene is fairly safe from an indoor-air-quality standpoint. Because of the open-cell structure, volatile chemicals left over from the reactants offgas quickly. The Saskatchewan Research Council tested Icynene in May 1994 and found that after 30 days, offgassing of five different VOCs virtually ceases. Green-Eclipse Inc., which runs the Envirodesic™ certification program for healthy buildings, lists Icynene as the only recommended insulation material. A Toronto developer is currently building a 115-unit subdivision of Envirodesic-certified homes, all of which will be built using Icynene. 

  Am I missing some thing here?  I'd appreciate the feedback.  Thanks,

  Jill Edelman, RA

"George J. Nesbitt" <geoedb at idiom.com> wrote:
  Bad insulation is better than no insulation.
Good insulation is better.
More insulation is better (concept Americans have a hard time with 
except for everything else).

Lawrence Lile wrote:

>I've rented a blower and put cellulose into old farmhouses that I owned.
>It is not a hard job if you know how to finish sheetrock. Just punch a
>hole in the wall, and fill it up! Hey, if it settles, it is still way
>better than it was before. We've also done it through the siding, with
>a big hole saw (and the electricity shut off). This is especially good
>if you want to add a layer of foam and re-side. 
>
>However, the pro's can do the whole job for not much more than I'd pay
>for the insulation at a hardware store, I haven't considered DIY
>cellulose for many years. 
>
>--Lawrence
>
>
>
>-----Original Message-----
>From: greenbuilding-bounces at listserv.repp.org
>[mailto:greenbuilding-bounces at listserv.repp.org] On Behalf Of Jefro
>Sent: Thursday, July 27, 2006 11:42 AM
>To: Greenbuilding
>Subject: [BULK] Re: [Greenbuilding] Cellulose settling
>Importance: Low
>
>Does "DIY cellulose" mean renting a blower and installing cellulose into
>cavities on one's own? I didn't know that was a possibility.
>
>We are building a home this fall using cellulose inside a 9-inch cavity
>built from a 2x10 plate and a double 2x4 wall. We have been planning to
>find an installer to use wet-blown cellulose. I am very interested to
>hear about other options, although I do have concerns about settling. 
>Please continue to discuss!
>
>thanks
>
>
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