[Greenbuilding] Foam insulation advice needed

Michael O'Brien obrien at hevanet.com
Tue Jun 14 17:22:40 CDT 2011


Hi, all--

Good point, Steve. Perhaps the situation will get better in the future, as our nation gets busy weatherizing all houses to adapt to climate change.  ;^ )

The only completely non-toxic insulation I could find available locally was damp-spray cellulose, and that was practical only because our general contractor had purchased a specialized spray machine. It worked fine for wall cavities. We used blown-in cellulose for the flat attic. I like these materials.

Our challenge was a vaulted ceiling. A friend once tried blowing in cellulose with a netting over rafters but the stuff went everywhere, and it was hard in the haze not to overfill cavities, which led to cranky drywallers. 

There used to be a non-toxic cementitious spray dealer in our area, but he went out of business. I heard that, years later, the stuff shrank and pulled away from the wood. Don't know about that but probably worth checking.

I think foam cement products are non-toxic but they can't achieve the R-values we need to meet code without putting them into assemblies that get complicated and costly.

Anyway, just musing on the search for really sustainable insulation materials that are practical and affordable. Whatever happened to mushroom insulation?

Best,

Mike O'Brien




On Jun 14, 2011, at 2:32 PM, natural building wrote:

> I shake my head in sad disbelief at products (and the discussion of products) that claim 'low-VOC' characteristics.
> We humans have a notoriously poor sense of smell, so any scale that is somehow linked to this is demonstrably flawed, and it makes me feel sad for the dogs and cats that also have to inhabit these houses that probably smell intolerably toxic.
> 
> Regards,
> Steve Satow
> 
> www.naturalbuildingsite.net
> naturalbuilding at shaw.ca
> 
> On 2011-06-14, at 1:35 PM, David Posada wrote:
> 
>> Bobbi,
>> Many sources agree that the two-part SPF chemicals are a health hazard during installation (so installers need to wear masks and suits) until the two parts cure. If installed properly and once they are cured, they are not supposed to off-gas any further.
>> 
>> There a long discussion (141 posts) on spray foam that continues off-gassing over at GreenBuildingAdvisor.com. The original Q&A post was "Out-gassing of bad stuff from spray foam insulation." (link is below) I posted an observation of the demi lec  foam you're considering at post #17 on 2/22/2010. The product is a low-density spray polyurethane foam similar to icynene. 
>> 
>> In this installation, the areas with a thin spray-on application (open 2x4 stud bays in one room, and basement rim joists) cured quickly and were odor free. The area with the thick application of 8-10" in an enclosed crawlspace and unvented low attic continued to off gas a noticeable sweet/ ammonia odor for many months.
>> 
>> I can only speculate on the possible cause(s): 
>> -- whether the lack of ventilation into the space during installation made a difference (I've heard it is advisable to vent the area well for the foam to cure properly), 
>> -- whether the mix of the part A and part B of the foam was incorrect (I've heard the particular smell can be from a catalyst-rich mix), or 
>> -- whether a thick application prevents the initial material from getting enough air to cure properly.
>> 
>> http://www.greenbuildingadvisor.com/community/forum/green-products-and-materials/14537/out-gassing-bad-stuff-spray-foam-insulation
>> 
>> It looks like people have continued adding comments to that thread even in recent months. 
>> 
>> David
>> 
>> 
>> Date: Mon, 13 Jun 2011 12:54:23 -0500
>> From: Bobbi Chukran <bobbi.chukran at suddenlink.net>
>> To: Green Building <greenbuilding at lists.bioenergylists.org>
>> Subject: [Greenbuilding] Foam insulation advice needed
>> Message-ID: <C31A8FD8-F7AD-41A3-935E-E21053333030 at suddenlink.net>
>> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>> 
>> We finally got some info. from the insulation guy for our new/old home.
>> 
>> He proposes using an open cell foam, Demilec Selection 500 in the  
>> attic rafters.  I'm concerned because even though the company has  
>> LEED ratings, etc. that product is still polyurethane based.
>> 
>> I mentioned that I wanted water-sprayed, and indeed that product is,  
>> but I'm still leery of the health issues.  Since I'm chemically  
>> sensitive and have asthma, and since we'll be working in the house  
>> (although I won't be in the attic) for months, then living in it, I  
>> have to be cautious.
>> 
>> All of the green building info. sites say it's a great product for  
>> insulating a home.  But what about the health of the inhabitants?   
>> That's what I have to worry about, foremost.
>> 
>> Any cautions, comments, etc. about this product?  Thanks!
>> 
>> bobbi c.
>> Leander and Taylor, TX
>> 
>> ***
>> 
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