We’re Moving!
We received the green light – we’re moving in. The house looks spectacular and everything seems to be working as designed and to its function. Living in the space will give a more accurate perspective but from having had some time to get to know the place over the last few months, it amazes us how enjoyable the results of a little planning can be.
November 16th, 2009 at 11:34 pm
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
November 17th, 2009 at 10:41 am
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