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November 11, 2021
Client: Jefferson Electric LLC, 2114 E Washington St, Indianapolis, IN 46201
Project Address: 1520 Heathrow Court Carmel, IN 46033
Subject: Structural Roof Evaluation
To Whom It May Concern:
We have reviewed the documents provided by Jefferson Electric relating to the installation of the
solar array at the above- referenced site. Based upon our review, it is our conclusion that the
installation of the solar array on this existing roof will not adversely affect this structure. It is our
understanding that the structural components of the existing roof framing are in good condition
and free of damage. The design of the solar panel racking (mounts, rails, etc.) and attachment is
by the manufacturer or contractor. Please note a representative of Synergy Engineering has not
physically observed the roof framing.
Design Parameters
Code: International Residential Code,
Risk Category: II
Design wind speed: 115 mph (3-sec gust)
Wind exposure category: B
Ground snow load: 20 psf
Conclusions
Our conclusion regarding the adequacy of the existing roof is based on the fact that the additional
weight of the solar array and attachment hardware is 3 psf or less. In the area of the solar array,
other live loads will not be present or will be greatly reduced. Evaluation of expected loads and
stress increase of the wood framing was made and shows sufficient reserve capacity in the roof
framing members. Regarding snow loads, because the panels are slippery and unobstructed,
effective snow loads will be reduced in the area of the solar array. The gravity loads in the area of
the solar array are decreased; thus, the stresses of the structural elements are decreased. Based on
these items plus the allowance in the IBC for an increase in force of up to 5% per section 3403.3,
the proposed solar array is structurally acceptable to install per the areas shown in the
following layout drawing.
Regarding lateral loads, the solar array will be flush-mounted (no more than 6" above the roof
surface) and parallel to the roof surface. Thus, we conclude that any additional wind loading on
the structure related to the addition of the proposed solar array is negligible. The connections to
the existing roof shall be spaced at 48" maximum. Because the increase in lateral forces is less
than 10%, this addition meets the requirements of the exception in Section 3403.4 of the IBC.
Thus the existing structure is permitted to remain unaltered.
12/01/21