HomeMy WebLinkAboutBLD-23-1709 affidavit 2/2Yarmouth, MA September 9, 2022
Town of Yarmouth1146 Route 28
S. Yarmouth, MA 02664
Trinity Solar No.
87 Stratford Lane 2022-05-703147
Yarmouth, MA 02675
RE: MARCELINE, JOHN M; COLLINS, CHARLOTTE
Trinity Solar | 20 Patterson Brook Rd, Unit 10 | West Wareham, MA | (508) 291-0007
MA License No. 56687
To the Building Official:
The following information constitutes a summary of the relevant design criteria and recommendations for the support of a
new photovoltaic [PV] system on the existing roof framing components at the above-referenced location.
Criteria is as follows:
1. Existing roof framing:
Conventional roof framing is 2x8 at 16 o.c.; existing rafter span= 18' 0" with an existing load bearing wall limiting rafter
span to 12' 4"; (horizontal projection)
2. Roof Loading:
• 3.0psf dead load (pounds per square foot - PV panels, mounting rails & hardware)
• 6.3psf - existing roof loads (2.3 psf - 2x8 framing, 1.5psf roof sheathing, 2.5 psf shingles)
• Ground Snow Load - 30psf - per AHJ (Authority Having Jurisdiction)
• Wind criteria - Exposure Category B, 140 mph wind
3. Existing Roof modification - none required; existing roof framing is acceptable for PV installation.
This installation design is in general conformance with the manufacturers’ specifications and complies with all applicable
laws, codes, and ordinances – specifically the International Building Code (2015 edition) and the International Residential
Code (2015 edition), including all Massachusetts regulations and amendments.
The spacing and fastening of the mounting brackets is a maximum of 48” o.c. between mounting brackets (staggered) and is
secured using 5/16” diameter corrosive-resistant steel lag bolts. A minimum of 2½” of penetration (embedment) per lag bolt
is required, which will resist all stated loads above – including wind shear. Per NDS Section 12.1.4, clearance holes - equal
to the diameter of the shank - need to be bored into a primary framing member for the full-length of the threaded portion of
the bolt to avoid splitting of the framing member.
Regards,
Ihor Bojcun, PE
Structural Engineer - Trinity Solar