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AOstructures Inc. <br />PO Box 413 <br />Carnelian Bay, CA 96140 <br />916.541.8586 <br />www.AOstructures.com <br />Per 10% lateral exemption of 2025 CBC - Existing Building Code - Section 503.4 <br />Level Area Weight (psf) Weight (lb) <br />Roof 39,083 sf 16.0 psf 625,328 lb <br />Ceiling 0,000 sf 0.0 psf 0,000 lb <br />Ext. Walls 374 ft 75.0 psf 336,600 lb (24'-0'' Wall Height) <br />Int. Walls 0 ft 10.0 psf 0,000 lb <br />Existing Weight of Effected Building 961,928 lb <br />Weight of PV System (Per Xero Solar) 3.0 psf <br />Approx. Area of Proposed PV System 5061 sf (Includes weight from adjacent system) <br />Approximate Total Weight of PV System 15,183 lb <br />10% of Existing Building Weight (Allowed) 96,193 lb <br />Approximate Weight of PV System (Actual) 15,183 lb <br />Percent Increase 1.6% <br />LATERAL CHECK OF EXISTING LFRS <br />Proposed Weight of PV System <br />96193 lb > 15183 lb, Therefore OK <br />10% Comparison <br />Methodology: The proposed PV array will be uniformly distributed about the roof surface. Therefore, it is reasonable to assume that the <br />seismic force applied from the PV array will be uniformly distributed back into the underlying roof diaphragm and existing lateral force <br />resisting system. The increase in lateral load to the building will be held to a maximum increase of 10% as per the limitations of the 10% <br />exemption of the existing building code. Due to the fact that seismic load is directly proportional to the weight of the building, the net <br />increase in seismic mass of the roof diaphragm will be be held to a 10% increase. The existing seismic mass at the roof diaphragm level <br />is equivalent to the weight of the roof and 1/2 of the walls below. <br />Existing Weight of Effected Building <br />1671 - Westridge Labs, Santa Ana, CA.xlsx 10