[Greenbuilding] embodied energy was Polyiso strength on roof (ErgoDesk)

[Norbert Senf]

I had a client a number of years back, a retired engineer, who did a deep
energy retrofit on an old concrete block schoolhouse that was basically
unheatable. There is a detailed description of his project here:
http://www.builditsolar.com/Projects/SolarHomes/SchoolHouseRetrofit/Main.htm

On Fri, Dec 12, 2014 at 10:36 AM, Alan Abrams <alan at abramsdesignbuild.com>
wrote:
>
> to me, the question is immediate. A current project is the gut rehab of a
> modest '40's house, with walls made of stuccoed concrete block. It is
> compelling to insulate the walls on the exterior, to provide as much
> interior area as possible, and to harness the thermal mass by optimizing
> solar gain and shading. But the climate is swampy in summer, and the house
> is situated near an old water course. So the potential to create a mold
> incubator is significant--particularly if winters become warmer and wetter.
>
> Current thinking is to fasten treated 2x's directly to the masonry, with 1
> 1/2" thick Roxul Comfort Board installed between members. The 2x's go on
> first to assure a good mechanical connection to the masonry. Then cover
> that with a continuous layer of more RCB, a good breathable WRB, furring,
> and back vented siding.
>
> another option would be mastic adhered EPS, and synthetic stucco. Or EPS,
> with furring secured through the foam into the masonry. This option strikes
> me as very risky, drilling through the furring, foam, and CMU, to provide
> pilot holes for Tapcons or similar fasteners. The length of the fastener
> becomes a serious limitation, too--not only their availability, but their
> cost. And for any variant using EPS, more reliance on mechanical
> dehumidification.
>
> The roof is another opportunity for muddling. The plan is to remove the
> entire second story, which had grown haphazardly over the years. Many
> advantages here--a single occupant already with one bionic knee--less
> volume to temper, lower real estate taxes. (making this project a
> "subtraction" instead of a more typical addition...)
>
> A quick and easy solution would be a set of SIPS, set on a low pitch.
> Alternately, simple engineered roof trusses, with loose fill something or
> other. The one is simple and direct, easy to create tuned overhangs. The
> other, conventional, breathable. Cost will probably be the determining
> factor.
>
>
> AA
>
>
>
> On Fri, Dec 12, 2014 at 9:09 AM, Alan Abrams <alan at abramsdesignbuild.com>
> wrote:
>>
>> not to muddy these already murky waters, but there are at least two other
>> factors that come into play.
>>
>
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-- 
Norbert Senf
Masonry Stove Builders
25 Brouse Road, RR 5
Shawville Québec J0X 2Y0
819.647.5092
www.heatkit.com
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