[Greenbuilding] Cathedral Ceiling & Icynene Insulation

[Lance Fletcher]

This seems to be one of those questions that's still open to debate. On the 
subject of roofing manufacturers' warranties, however, the only 
manufacturers that I am aware of who will warranty a hot roof (no 
ventilation layer) are Elk and, in some instances and with some limits, 
Certainteed. The last time I checked -and I check regularly at trade shows, 
etc- none of the others would.

If anyone knows of another manufacturer that does warranty their shingles 
over a hot roof, I'd like to hear about them. Elk is not commonly 
distributed in my area.

Lance Fletcher, AIA, LEED
14 South Freeport Road
Freeport, ME 04032

207.865.3611
lfletcher at rcn.com
----- Original Message ----- 
From: "Alan Abrams" <alan at abramsdesignbuild.com>
To: <greenbuilding at listserv.repp.org>; "'Ron Hays'" 
<ronhays at cascadeaccess.com>
Sent: Sunday, May 20, 2007 10:27 AM
Subject: Re: [Greenbuilding] Cathedral Ceiling & Icynene Insulation


>
>   Ron--we got approval to do this in Montgomery County, MD back in 2003, 
> and
>   it  has  become  our  standard  for stick construction since then, for
>   "cathedral" ceilings, fully insulated attics, and flat roofs as well.  I
>   believe it is approved by the ICC, too, but i'm at home without a code
>   book...
>
>   See:
>
>   http://www.icynene.com/assets/documents/PDFs/Vol12_04_EarthCraft.pdf
>
>
>    "By its nature, Icynene® requires no ventilation space from
>   soffit to ridge, which increases design freedom for both the exterior 
> and
>   interior of the house. Icynene® is intended to fill all of the gaps and
>   crevices, thus eliminating the need to leave a path for air ventilation
>   within the rafters."
>
>
>   and
>
> 
> http://www.icynene.com/assets/documents/PDFs/RLS-ICC%20Approves%20Unvented%2
>   0Attics.pdf
>
>   Shingle manufacturers will reduce their warranties in some cases without 
> a
>   ventilated roof deck, but i suspect this is substantially a canard.
>
>   It's  also advisable to make sure there are no paths from the basement
>   through wall cavities into any transitions from wall to ceiling.  to be 
> on
>   the  safe  side,  develop  strategies  to prevent the house from being
>   depressurized, by bath or kitchen vents, for example.  avoid recessed 
> lights
>   in the ceilings like the plague.
>   Alan Abrams AIBD
>   Abrams Design Build LLC
>   202-726-5894 o
>   202-291-0626 f
>   www.abramsdesignbuild.com
>   On Sat May 19 23:40 , "Ron Hays" sent:
>
>     I'm building a bathroom addition for a client in Portland, OR with a
>     cathedral ceiling (3 on 12). The house is a 1920's bungalow style home 
> and
>     the client has had the rest of the house in the house insulated with
>     Icynene
>     foam insulation sprayed between the 2x4 rafters in the attic, eve and
>     vaulted ceiling areas. He wants to spray the vaulted ceiling of the 
> shed
>     dormer addition with Icynene also. However, the building inspector is
>     concerned that if the cavity is fully filled and no ventilation 
> beneath
>     the
>     sheathing the roof will degrade because of heat built up. I know this 
> is
>     conventional wisdom. Is there any recent research that indicates that 
> it
>     is
>     OK to fully insulate the joist space.
>     Ron Hays
>     Eagle Creek Natural Building
>


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