7910 W GLEN DR 2023-06-15 - Laserfiche WebLink

SOLGEN P O W E R May 22, 2021 Subject: Proposed Solar Panel Installation Ronald Hendee Residence, 7910 W Glen Dr., Everett, WA 98203 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 (20181 BC) Risk Category: ll Design Wind Speed: 97 mph (per ASCE 7-16) Ground Snow Load: 10 psf Roof Information Roof Structure: 2x8 Rafters @ 24" O.C. Roofing Material: Asphalt Shingles Roof Slope: 21 degrees Roof Connection Details Lag Screws. 5/16" diameter min., with min. 2.5" embedment into framing members, at 48" O.C. min, staggered Locations per design drawings Note: aegain d embedment length excludes the tapered tip of the screw, and embedmerd into sheathing. Analysis The proposed Installation - including weight of panels, racking, and mounts - will be approximately 2.56 psf. In the areas where panels are installed, roof live loads will not be present. Also, where applicable, roof snow loads will be reduced because the slippery surface of the panels will cause the roof to shed additional snow loads relative to the existing roof surface. The reduction of roof live and snow 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 807.4 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 907.5 of the adopted IEBC, the structure need not be altered for lateral loading.