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PPurefight Power <br />March 01, 2024 <br />Subject: Proposed Solar Panel Installation <br />Gonzalo Negrete Residence, 2422 Cedar St, Everett, WA <br />To Whom it May Concern, <br />Our engineering department has reviewed information, gathered by our field crews, related to the proposed solar <br />panel installation at the above -referenced address. The purpose of our review was to determine the structural <br />adequacy of the existing roof. Based on our review and analysis of the available information, and in accordance with <br />governing building codes, it is our professional opinion that the existing structure is permitted to remain unaltered <br />for the proposed solar installation. <br />Design Parameter Summary <br />Governing Building Code: 2018 Washington Building Code (2018 IBC) <br />Risk Category: II <br />Design Wind Speed: 110 mph (per ASCE 7-16) <br />Ground Snow Load: 15 psf <br />Roof Information <br />Roof Structure: 2x4 Manufactured Trusses @ 24" O.C. <br />Roofing Material: Asphalt Shingles (1 layer) <br />Roof Slope: 20' <br />Roof Connection Details <br />Lag Screws: (1) 5/16" diameter min., with min. 2.5" embedment into framing members, at 48" O.C. max, staggered <br />Locations per design drawings <br />Note: Required embedment length excludes the tapered tip of the screw, and embedment into sheathing. <br />Analysis <br />The proposed installation complies with the requirements of WAC Section 51-51-03240 R324.4 (Exception) and is <br />therefore deemed adequate to support the load of the rooftop solar system. <br />Specifically: 1) the system is designed for the local wind speed; 2) the ground snow load does not exceed 70 psf; 3) <br />the total dead load of all items is less than 4 psf (actual value is approximately2.75 psf); 4) Modules are not mounted <br />more than 18" off the roof; and 5) Supports are installed such that the dead load is spread across roof -framing <br />members and does not exceed 50 Ibs at any point. <br />Wind uplift on the panels has been calculated in accordance with the relevant provisions of ASCE 7-16. This loading <br />has been used to verify the adequacy of the connection specified above. Connection locations should be in <br />accordance with design drawings. <br />