[Greenbuilding] Metal roofing retrofit (was Re: Air Conditioning for Phoenix)

[Rob Tom]

On Wed, 31 Jan 2007 18:18:03 -0500, Ben Pratt <prattb at uwstout.edu> wrote:

> The only part my little brain didn't get was where the insulation would  
> be installed.

>> it would be possible to install standoffs that place a  new rafter at 
>> some desired distance (say 18-24") that would effectively turn the  
>> existingrafters into parallel chord trusses

Ben;

Turning your existing rafters into 18-24" deep parallel chord trusses  
accomplishes at least four things:

(1) Strengthens the existing rafters.
(2) Creates an enormous cavity on top of your existing roof that will  
accomodate superinsulation levels of non-plast-ecch!! (and less-expensive)  
fibrous insulation
(ie Roxul mineral wool)
(3)Allows extension of eaves to create desired overhangs
(4) Allows new roof to be created with minimal disruption to existing roof.
     ie The rafters in your existing roof become the bottom chord of the
       new parallel chord truss.


=== * ===
Rob Tom
Kanata, Ontario, Canada
<A r c h i L o g i c   at  c h a f f y a h o o   dot   c a >
winnow the chaff from my edress in your reply