HomeMy WebLinkAbout1706 Briargate Ct - Correspondence/Solar - 08/19/2015Lopez Snlolens Associates
Consulting Structural Engineers
August 19, 2015
To:
Re:
SunTalk Solar n
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9900 E. 51st Ave. �2..
9
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Denver, CO 80238
General Flush -mount PV Installation Letter
Plans Examiner,
Engineering Project #: 515516
This is a general, prescriptive letter for the installation of flush -mount solar PV arrays on existing roofs in the
State of Colorado. Our review, based on the 2015 IBC, confirms that roofs will be adequate to support the
added loads from the arrays given the following parameters:
1) The design roof snow load does not exceed 30 psf. The design wind speed does not exceed 130 mph,
3-sec gust (Vasa). The array and racking dead load does not;exceed 5 psf.
2) The existing roof structure is pre-engineered wood trusses at 24" spacing constructed in 1980 or later
that have a minimum roof pitch of 4/12 and a maximum pitch of 12/12. Trusses have vertically -
oriented nominal 2"-wide members. ,.Flat 2x purlins are not covered in this letter.
3) The existing roofing material is a single layer of asphalt shingles. Multiple layers and other roofing
materials are not covered in this letter.
4) Mounts from the panel rails are spaced at 48" maximum (on the 24" o.c. trusses). Vertically -adjacent
mounts do not bear on the same truss but are staggered over every other truss (wherever possible) so
that each truss under the panels supports some load. Mounts are also within 16" of array edges.
5) The mounts are attached to the trusses with 5/16"-diameter stainless steel lag screws with a minimum
penetration of 2" into the center of the 2x truss top chords.
6) The array does not hang below the roof eve, extend above the roof ridge, or beyond the roof edges.
7) The array has a maximum clearance off the roof surface of 10".
8) Existing roof trusses that support the array have been verified to connect to bearing walls with
Simpson H2.5 hurricane ties, or equivalent, minimum. '
This letter has been written for the exclusive use of SunTalk Solar and Lopez Smolens Associates. If any of the
above descriptions or specifications are not satisfied, this letter does not apply. We do not assume
responsibility for any construction flaws or defects that may be caused by the proposed installations.
Sincerely,
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Ian M. Smith, P.E. Si ' • �j
2400 Central Ave., A-1 North, Boulder, CO 80301 (303) 447-2813 fax (303) 447-2814