[Greenbuilding] Cellulose settling

Thu Jul 27 12:14:34 CDT 2006

Yes, the blow-in fiberglass is getting popular around here (DC area). FG 
makes me itch just thinking about it. I have deep-seated suspicions, I'd 
be interested if anyone has any further information about it's 
advantages & disadvantages. It seems likely to me that it has much 
higher embodied energy than cellulose, and of course it doesn't utilize 
a recycled waste stream. What about off-gassing (in both cases!)? 
Anything else? Both the fiberglass & cellulose industries have always 
argued that they're better in case of fire -- anyone have any objective 
sources? I tend to underplay air quality with respect to fibers in both 
cases, since the fibers are too big to osmose through an air barrier, so 
they should only be a concern during installation. That may not be 
accurate, and clean up shouldn't be underestimated, especially in the 
case of DIYers or chemically sensitive (which perhaps we all are, more 
than we know).

Keith

John Straube wrote:
> I agree with Loren -- there are no facts to support the contention that a
> DIY dense pack will be a problem.
> It is pretty hard to screw up dense pack cellulose or even damp spray
> relative to other types of insulation. DIY insulation is almost always
> installed better since the installer really cares and spends lots of time.
> Weatherization people from all areas of the country who insulate homes and
> then infra-red camera inspect constantly tell me that cellulose installs
> better than any other practical insulation based on real-life inspections.
> Some fibreglass products are now appearing that are blow-in and spray in (eg
> JM Spider)to solve some of the poor quality install issues FG has. 
>
> Dr John Straube
> Associate Professor
> Dept of Civil Engineering & School of Architecture
> University of Waterloo
> Waterloo, Ont., Canada
> www.civil.uwaterloo.ca/beg
>  
>
> -----Original Message-----
> From: greenbuilding-bounces at listserv.repp.org
> [mailto:greenbuilding-bounces at listserv.repp.org] On Behalf Of Laren Corie
> Sent: Thursday, July 27, 2006 10:07
> To: greenbuilding at listserv.repp.org
> Subject: Re: [Greenbuilding] was Diminishing returns / obsessingover
> bridging
>
>
> "Lawrence Lile" <LLile at projsolco.com>
>
>   
>> DIY blown-in cellulose, installed between existing studs
>> and not done by a pro will probably settle and have gaps.
>>
>> --Lawrence Lile
>>     
>
>      I have seen no factual basis for such a statement.  There have
> definitely been bad blown-in wall installations, by unscrupulous pros who
> have cheated homeowners by using too little material. However, there is
> nothing to suggest that a DIYer would ever short himself, when the only way
> to tell that the wall cavity is full is that the blower stops moving
> insulation and the hose buckles.  You simply fill the hole until it won't
> take any more insulation. Cellulose will naturally
> settle to roughly 1-1/2 lbs/cu ft density.     It gets blown into walls
> at between 3.25 and 3.75 lbs/cu ft. So, it is packed in way tighter than its
> natural settling density (like a spring, or foam rubber in a cushion).
> Vibration will not cause it to settle. It does the opposite. It will cause
> it to expand into every tiny area. Since there is far more cellulose in the
> wall cavity, than its natural settling density, it simply can not slump. It
> would be highly unusual for any area of a wall cavity to remain empty when
> that same cavity was filled with insulation.  Locating the holes is not a
> complicated task.  A hole near the top, and another near the bottom, will
> give even enough packing for no slumping to occur in normal height walls.
> Taller walls simply get an additional hole. Since the insulation value of
> cellulose is in the fibers, instead of in the gaps between, there is no loss
> of R value by increasing the density over that used for loose fill
> installations. At either its loose fill density, or the 'dense-pack'
> density, the R value is around 3.7-3.8/in.
>
> However, there has been evidence that some foam insulations
> can lose their bond with studs, leaving gaps where air can pass.  This is
> why gaskets are beginning to be used around windows and doors, instead of
> foam fills. This loss of contact should not happen with 'dense-packed'
> cellulose, even in 
> narrow spaces, where there might be frame movement.
>
> -Laren Corie-
> Natural Solar Building Design Since 1975
> www.LarenCorie.com
>
> -LittleHouses- http://groups.yahoo.com/group/LittleHouses
>
> -WoodGas- http://groups.yahoo.com/group/WoodGas
>
> -Energy Self-Sufficiency Newsletter- Free at  www.rebelwolf.com
>
> -Refrigerator Alternatives-
> http://groups.yahoo.com/group/RefrigeratorAlternatives
>
> _______________________________________________
> Greenbuilding email list
> List info:
> http://listserv.repp.org/mailman/listinfo/greenbuilding_listserv.repp.org
> List email: Greenbuilding at listserv.repp.org
> Managed by BuildingGreen, Inc. http://www.buildinggreen.com
>       publisher of Environmental Building News and GreenSpec(r) Hosted and
> archived by REPP / CREST http://www.crest.org
>
>
> _______________________________________________
> Greenbuilding email list
> List info: http://listserv.repp.org/mailman/listinfo/greenbuilding_listserv.repp.org
> List email: Greenbuilding at listserv.repp.org
> Managed by BuildingGreen, Inc. http://www.buildinggreen.com
>       publisher of Environmental Building News and GreenSpec(r)
> Hosted and archived by REPP / CREST http://www.crest.org
>
>
>
>
>   

-- 
Keith Winston
Earth Sun Energy Systems
3927 Madison St.
Hyattsville, MD 20781
301-980-6325
keith at earthsunenergy.com
www.EarthSunEnergy.com