HomeMy WebLinkAboutLA186552 - Approved letterARC Design
409 N. Main Street
Elmer, NJ 08318
(856) 712-2166 fax: (856) 358-1511
Construction Code Office
Date: November 24, 2020
Re: Roof Certification Letter
Subj: Biggs Residence, 19751 Henning Ave., Lakeville, MN 55044
We have provided a review of the roof constructions of the above named property in regards to
verifying the capacity of the existing roof for installation of a new Solar Panel Array.
We have found the structure to be of wood frame construction. The Roof is of 2x4 @ 24” o.c. truss
framed roof (half of the roof structure is a vaulted ceiling) and is sheathed with ½” ext-ply and a single
layer of composite shingle roofing.
The wood framed roof structure bears directly upon the framed exterior wall system. The existing
members as installed meet the required IRC-2018 with 2020 MN amendments design span ratings with
sufficient capacity to carry the 4#/sf additional load imposed by the proposed solar array per the details
below.
Installation of solar rack systems shall be as follows:
Each panel row shall be supported upon 2 mounting rails. Rails shall be screw anchored
through roof and directly to rafters below.
Rail attachment points to rafters shall be staggered each row with exception to the first fastener
row from the gable end which is attached to two adjacent rafters.
A roofing compatible sealant or shingle flashing kit shall be utilized at each mtg. foot location.
Solar panel mounting systems installed parallel to the plane of a roof shall be no more than 12"
above the roof when measured perpendicular to the roof surface.
When installed per the above specifications the system shall meet the required 115 MPH wind load and
50 PSF ground snow load requirements.
Should you have any further question or comment please feel free to contact our office.
Respectfully,
James A. Clancy
Professional Engineer
MN License # 45968