2127 OAKES AVE 2023-04-26 - Laserfiche WebLink

SOLGEN P O W E R July 13, 2022 Subject: Proposed Solar Panel Installation Stephen Ehresman Residence, 2127 Oakes 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 (2 layers) Roof Slope: 12 degrees Roof Connection Details RT Minis into 2x rafters or truss top chords at 48" O.C., install per design drawings and manufacturer specs Locations per design drawings Note: Required embedment length excludes the tapered tip of the screw, and embedment into sheathing. Analysis The proposed installation - including weight of panels, racking, and mounts - will be approximately 2.66 psf. In the areas where panels are installed, roof live loads will not be present. The reduction of roof live load is adequate to fully or partially compensate for the addition of the panel installation. Because the member forces in the area of the solar panels are not increased by more than 5%, the stresses in the members are not increased by more than 5%, and so per section 806.2 of the International Existing Building Code (IEBC), the structure need not be altered for gravity loading. The proposed installation will be 6" max. above the roof surface (flush mounted) and parallel to the roof surface. Therefore, any increase in wind loading on the building structure from the solar panel installation is expected to be negligible. Wind is the governing lateral load case. Because the increase in lateral loading is not increased by more than 10%, per section 806.3 of the adopted IEBC, the structure need not be altered for lateral loading. Wind uplift on the panels has been calculated in accordance with the relevant provisions of ASCE 7-16. This loading has been used to verify the adequacy of the connection specified above. Connection locations should be in accordance with design drawings. rnnrhicinn