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

[Drew A. Gillett P.E.]

calling it a parallel chord truss and making it work as one are two very 
different things. it's all in the joints which will be difficult thru the 
existing roof.
----- Original Message ----- 
From: "Rob Tom" <ArchiLogic at yahoo.ca>
To: "Ben Pratt" <prattb at uwstout.edu>
Cc: "GB REPP" <GREENBUILDING at listserv.repp.org>
Sent: Thursday, February 01, 2007 2:07 PM
Subject: Re: [Greenbuilding] Metal roofing retrofit (was Re: AirConditioning 
for Phoenix)


> 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
>
>
> _______________________________________________
> Greenbuilding email list
> List info: 
> http://listserv.repp.org/mailman/listinfo/greenbuilding_listserv.repp.org
> List email: Greenbuilding at listserv.repp.org
> Managed by BuildingGreen, Inc. http://www.buildinggreen.com
>      publisher of Environmental Building News and GreenSpec(r)
> Hosted and archived by REPP / CREST http://www.crest.org
>