Comments on: We’re Moving! http://imberaksehouse.ca/2009/11/16/were-moving/ Imber Akse House is the realization of our dream home. A burlington LEED home that looks at living, sustainability and urbanism in a holistic perspective. We've designed this site to engage as many people in the process of designing and building our sustainable home as possible — so that we might encourage others to take the same steps toward positive change and get there with a little more ease. Fri, 05 Mar 2010 01:29:47 -0500 http://wordpress.org/?v=2.8.4 hourly 1 By: Barry Imber http://imberaksehouse.ca/2009/11/16/were-moving/comment-page-1/#comment-4620 Barry Imber Tue, 17 Nov 2009 14:41:31 +0000 http://imberaksehouse.ca/?p=423#comment-4620 Thanks Harold, I'm not certain that truss technique applies to our flat roof construction but I might ask <a href="http://www.turkstratrusses.ca/" rel="nofollow">Turkstra Trusses</a> their opinion. The high heel truss application technique works with pitched roofs — creating an insulate-able gap between the truss and the roof deck at the point where they would traditionally have met. This new (or old) technique provides a gap where the insulation (hopefully blown foam) can fill the gap and provide an R-value greater than wood to wood which only provides a couple of R's in value - hence the leak. A quick google found this link: http://blog.projectgreenbuild.org/2007/09/28/raised-heel-truss-offers-energy-savings/ In our case, we have <a href="http://imberaksehouse.ca/wp-content/uploads/pict0064.jpg" rel="nofollow">12"+ deep engineered joists flush to the roof deck</a>. Though no insulation fits between the joists and the deck, the conductive 1/2" thick bridging (wood that connects the interior to exterior) of the joist body is very minimal compared to the 10" deep layer of closed cell spray foam that fills the ceiling space. I'm sure there is a better technique for increasing our average R-value of the flat ceiling/roof but this conventional method proved cost effective. Furthermore, the air gaps where the horizontal joist passes through or across the top of the wall to the exterior is eliminated with the expanding foam, an issue that plagues pitched roofs that don't use the high heel technique. In the end we achieved approximately <a href="http://imberaksehouse.ca/2008/12/11/insulation-jarvis-insulation/" rel="nofollow">R-40 performance</a> level which compares to easily twice that of conventional batt insulation. Good luck with the green reno! Barry Thanks Harold,
I’m not certain that truss technique applies to our flat roof construction but I might ask Turkstra Trusses their opinion. The high heel truss application technique works with pitched roofs — creating an insulate-able gap between the truss and the roof deck at the point where they would traditionally have met. This new (or old) technique provides a gap where the insulation (hopefully blown foam) can fill the gap and provide an R-value greater than wood to wood which only provides a couple of R’s in value – hence the leak. A quick google found this link: http://blog.projectgreenbuild.org/2007/09/28/raised-heel-truss-offers-energy-savings/

In our case, we have 12″+ deep engineered joists flush to the roof deck. Though no insulation fits between the joists and the deck, the conductive 1/2″ thick bridging (wood that connects the interior to exterior) of the joist body is very minimal compared to the 10″ deep layer of closed cell spray foam that fills the ceiling space. I’m sure there is a better technique for increasing our average R-value of the flat ceiling/roof but this conventional method proved cost effective. Furthermore, the air gaps where the horizontal joist passes through or across the top of the wall to the exterior is eliminated with the expanding foam, an issue that plagues pitched roofs that don’t use the high heel technique.

In the end we achieved approximately R-40 performance level which compares to easily twice that of conventional batt insulation.

Good luck with the green reno!
Barry

]]> By: Harald Ulrich http://imberaksehouse.ca/2009/11/16/were-moving/comment-page-1/#comment-4618 Harald Ulrich Tue, 17 Nov 2009 03:34:45 +0000 http://imberaksehouse.ca/?p=423#comment-4618 Congratulations ! The house looks awesome, what job !! You're going to love it. I'm finally starting my own (green) reno, and was wondering if you used 'high heel trusses' in your roof desing, to accomodate more insulation. thanks, Harald Ulrich Congratulations ! The house looks awesome, what job !! You’re going to love it. I’m finally starting my own (green) reno, and was wondering if you used ‘high heel trusses’ in your roof desing, to accomodate more insulation.
thanks,
Harald Ulrich

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