3730 WETMORE AVE 2023-10-31 - Laserfiche WebLink

SOLGLN P O W E R September 30, 2023 Subject: Proposed Solar Panel Installation Jessica Pisca Residence, 3730 Wetmore Ave, Everett,WA To Whom it May Concern, Our engineering department has reviewed information, gathered by our field crews, related to the proposed solar panel installation at the above-referenced address. The purpose of our review was to determine the structural adequacy of the existing roof. Based on our review and analysis of the available information, and in accordance with governing building codes, it is our professional opinion that the existing structure is permitted to remain unaltered for the proposed solar installation. Design Parameter Summary Governing Building Code: 2018 Washington Building Code (2018 IBC) Risk Category: II Design Wind Speed: 110 mph (per ASCE 7-16) Ground Snow Load: 15 psf Roof Information Roof Structure: 2x4 Rafters @ 24" O.C. Roofing Material:Asphalt Shingles(1 layer) Roof Slope: 14 degrees& 37 degrees Roof Connection Details RT Minis. Install generally into 2x rafters/chords, but up to 50% may be installed into decking only.48" O.C.. Install Lag Screws: 5/16" diameter min.,with min. 2.5" embedment into framing members, at 48" O.C. max, staggered Locations per design drawings Note:Required embedment length excludes the tapered tip of the screw,and embedment into sheathing. Analysis The proposed installation complies with the requirements of WAC Section 51-51-03240 R324.4 (Exception) and is therefore deemed adequate to support the load of the rooftop solar system. Specifically: 1) the system is designed for the local wind speed; 2) the ground snow load does not exceed 70 psf; 3) the total dead load of all items is less than 4 psf (actual value is approximately2.65 psf); 4) Modules are not mounted more than 18" off the roof; and 5) Supports are installed such that the dead load is spread across roof- framing members and does not exceed 50 lbs at any point.