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AOstructures Inc. <br />PO Box 413 <br />Carnelian Bay, CA 96140 <br />916.541.8586 <br />www.AOstructures.com <br />Gravity Check of Existing Wood Framed Roof Framing Members <br />Per the recommendations provided in Ꚃ7.2.1 of SEAOC PV3-2019 <br />Building code = 1994 UBC or more recent? YES (Constructed circa 2003) <br />Roof slope ≥ 1/4" per foot w/ drainage to prevent ponding?Assumed - See discussion in Appendix B - Contractor shall VIF <br />Applicable? YES <br />Roof Dead Load 16.0 psf <br />Roof Live Load 12.0 psf <br />Original Governing Design Weight of Roof - Before PV 28.0 psf <br />Allowed Load (5%) Increase 29.4 psf <br />Roof Dead Load 16.0 psf <br />Roof Live Load 5.0 psf (Conservatively assume a marginal amount of RLL) <br />PV Array 3.0 psf <br />Total Weight of Roof - After PV 24.0 psf <br />Allowed Load (5%) Increase 29.4 psf <br />Total Weight of Roof - After PV 24.0 psf <br />29.4 psf > 24 psf, Therefore OK <br />Total Weight of Roof - Before PV <br />Total Weight of Roof - After PV <br />Methodology: The proposed PV array is considered to be sufficiently uniformly distributed about the roof surface. <br />Therefore, it is reasonable to assume that the gravity force applied from the PV array will be uniformly distributed <br />back into the underlying roof framing system. The PV array will be no higher than 24" above the roof and be <br />inaccessible as defined per section 1607.14.4.1 (See verbiage below) of the Building Code. Therefore per the <br />same section, the roof framing elements below the PV array do not need to be designed for roof live load. A 5% <br />comparison to the loads prior to the installation of the PV array and after the installation of the PV array is <br />provided. The "after" loads are modified by a change to the load duration factor (Cd) due to a wood roof framing <br />system below. <br />5% Comparison <br />Exemption of Ꚃ7.2.1 of SEAOC PV3-2019 applicable? <br />1671 - Westridge Labs, Santa Ana, CA.xlsx 9