HomeMy WebLinkAboutB13-0153 Engineering Letter and Shop Drawing approvedISTRUCTURAL DESIGN
65 N4th ST,SUITE 5
CARBONDALE,CO 81623
(970)618-7708
(970)963-0265 -FAX
29029 UPPER BEAR CRK RD,#308
EVERGREEN.CO 80439
(303)670-0028 -phlfax
(720)626-920'-cell wW\V,evolvestruct.com
June 3,2013
Isaac Ellis
Sunsense Inc.
P.O.Box 301
Carbondale,CO 81623
RE:PV Panei Addition at the Pierce Residence
2730 Bald Mountain Road
Vail,CO 81657
Dear Isaac:
As requested we have reviewed the proposed photo voltaic panel addition at the residence noted above.Our analysis is
based upon the original drawings and specifications provided by Sunsense on ApAllO.2013.as well as the attached
updated layout dated June 3,2013.We have also reviewed the existing roof framing based upon existing structural
drawings provided by Venture Architecture,designed by Engineering Designworks dated April 4,2012.The existing
conditions shall be verified by contractor prior to construction.We shall be notified if conditions are found to differ
from that shown on the referenced set of existing structural drawings or as stated within.
The applicable current codes are the 2012 International Residential Code and the 2012 International Building Code per
the Town of VaiL The applicable structural design criteria are as follows:
Roof Dead Load
Roof Snow Load
Wind Criteria
20 psf'(assumed,including 3 psfPV panel &rack)
80 psf at modified roof area (7:12 wi slippery surface at panels)
90 mph,Exposure B
The existing roof framing is assumed to be 5/8"APA rated sheathing,40/20,spanning perpendicular over 11 718"I-joist
or LVL rafters,spaced at a maximum of24"0.c.The sheathing is assumed to be attached to the rafters with 8d common
nails at 6"0.c.at panel edges and at 12"0.c.to intermediate framing members.The design of the panels,the panel racks
and connections between shall be per the manufacturer for the applicable design criteria.For the layout and attachment
of the racks to the roofrefer to the Sunsense Fastening Layout on P-OS,dated AprilB,2013.Orion EZ Roof Mount L-
Foot Kit for shingle roofs shall be used for the connections to the existing roof,installed per manufacturer.Each circular
base plate shall be attached with (4)#12 x 2 W'Dekfast screws.Screws shall have a minimum y.,"through sheathing
penetration and (2)screws shall penetrate an existing rafter 12"minimum.The center ofthe L-Foot base plates shall be
located over the rafters.with a maximum tolerance of 1 \/,"to the center of rafter.
Per the design criteria,assumptions and recommendations stated above,it is our professional opinion that the existing
roof structure is adequate for the proposed PV panel addition.
Should you have any further questions regarding this matter,please feel free to contact our office.
Sincerely,
Evolve Structural Design LLC
Sara Mickus,P.E.
Principal
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SOLAR I DESIGN I BUilD
PIERCE RESIDENCE
6.24 kW Photovoltaic System
NOTES:
1)Roof Structure:12"TJI-24"OC
2)Roof Material:Wood Shingle
3)Racking System:P8 Power Rail SITE ADDRESS:2730 Bald Mountain Rd.
Vail,CO 81657
REVISION:C DATE:6/3/13
DRAWN BY:IJEP.O.Box 301
Carbondale,CO 81623
P 970.963.1420
F 970.963.1496