flat rubber roofs [RE-wrenches]

[Jeff Clearwater]

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Geoff,

YES - what Brad Said!

You can get most 5º systems down to 5 lbs/ft2 or 
even less.   but as Brad says YOU GOTTA CHECK OUT 
IF THE ROOF WILL EVEN HOLD THAT AND SNOW!  No 
more Poland pigeon repeats please.  The roof we 
did in northern MA had 20-25 lbs/ft2 safety built 
in so no problem but we confirmed first with the 
building's original engineer.  Most commercial 
roofs are built to handle air conditioners etc. 
but some are not.

Jeff C.




>
>Geoff,
>
>You really should have an engineer look at the structure. I remember
>quoting a US post office job and when the engineer looked at it, he said
>the building did not meet code as is, and said he would not be surprised
>if it would collapse in the next really heavy snow (I haven't heard that
>it has yet, but maybe no heavy snow there... yet). He would not OK
>putting ANYthing on the roof. And this was a govt. building.  So I don't
>think you can assume any roof is strong enough without taking a look.
>Residential roofs are standard enough that you can probably judge it,
>but maybe not commercial roofs.
>
>Brad
>AEE
>
>
>geoff at third-sun.com wrote:
>>
>>  I have a project with a flat rubber roof on an older townhouse style 3
>>  story
>>  apt. building. shading etc wants to put our PV all in one spot... trying
>>  to
>>  rack 21 evergreen panels at 26 degrees... (flexible on that)  My initial
>>  idea is to do a conventional tilted mounting system attached to some
>>  wooden
>>  curbs that I would have flashed and "roofed" onto the existing roof by a
>>  sub.  The quotes are coming in surprisingly high ($4-5K for (6) 8'
>>  curbs).
>>  Is this normal? I actually do have access to the 2x12s from below - I
>>  could
>>  probably put in blocking and use single point standoffs - would this be
>>  a
>>  less expensive approach?  Maybe I should look at a ballasted approach? 
>>  I
>>  have thought of hefting some pre-cast concrete lintels or parking curbs
>>  up
>>  there and using masonry fasteners to attach to them but I certainly
>>  don't
>>  want to rough guess the required weight...How would YOU do it?
>>
>>  For a brighter energy future,
>>
>>  Geoff Greenfield
>>  NABCEP Certified Energy Practitioner
>>
>>  THIRD SUN SOLAR & WIND POWER Ltd.
>>  340 West State Street
>>  Athens, OH 45701
>>
>>  www.third-sun.com
>>  (740) 597-3111
>>
>
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-- 
~~~~~~~~~~~~~
Jeff Clearwater
Village Power Design Associates
Sustainable Energy & Water Solutions for Home & Village
http://www.villagepower.com
gosolar at villagepower.com

530-470-9166
877-SOLARVillage
877-765-2784
425 Nimrod St.
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