[Greenbuilding] Foam installed between framing during framing

[Gennaro Brooks-Church - Eco Brooklyn]

Eli,
I don't see the detailed description. I presume the joists etc are
wood? If metal than the plan is not viable. If wood it would work
provided you tape the insulation to the wood to create a complete air
seal. You need to use a tape like Tescon since 99% of the tapes won't
stick for long.
http://de.proclima.com/produkte/verbindungsmittel/klebebaender/tescon-vana
Or apply a vapor permeable barrier and tape it off to create an
airtight seal. This can be done before or after the insulation is
applied.
In both tape or vapor options I would seal all gaps between insulation
and wood with spray foam since any air space will conduct heat.
I would also use PolyISO instead since it has a higher R value.
Putting the insulation over or under the wood is a lot less labour and
creates a better seal but I suspect you can't put it over and you want
the space under.
Gennaro Brooks-Church
Director, Eco Brooklyn Inc.
Cell: 1 347 244 3016 USA
www.EcoBrooklyn.com
22 2nd St; Brooklyn, NY 11231


On Thu, Jan 3, 2013 at 11:57 AM, Frank Tettemer <frank at livingsol.com> wrote:
> While Building "Science" uses exacting figures, and also really know their
> stuff,
> my take on Building "Construction" says Ixnay with the precut EPS squeezed
> between truss top cords.
>
> My reasoning for this statement is around the huge amount of opportunities
> for leaks, due to:
> possible inaccuracy in cutting the EPS.
> fitting the EPS around the metal truss plates holding all the cords
> together.
> the inevitable wood movement, (designed in by Mother Nature), of the truss
> members,
> as well as the fact that most top chord members of commercially constructed
> trusses are 2"x3" or 2"x4" in width, which is not very much thickness for
> the EPS insulation, as far as R-value is concerned.
> It is my take on it that trying to make a conditioned and useful space out
> of an attic has more problems associated than there are solutions.
> However, I could be wrong about this.
>
> Frank Tettemer
> ...........................................................................................
>
> Eli Talking:
> I am wondering if it would be reasonable to install accurately precut eps
> foam between joist, rafters, or top chord of truss during the framing to
> achieve a cheap relatively tight installation when compared to fiberglass
> with the air seal being achieve outside the framing with continuous 6” eps
> foam managed for air tightness. More detailed description is below.
>
> --
> Frank Tettemer
> Living Sol ~ Building and Design
> www.livingsol.com
> 613 756 3884
>
>
> _______________________________________________
> Greenbuilding mailing list
> to Send a Message to the list, use the email address
> Greenbuilding at bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org