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OBSERVED CONDITIONS: <br />CONCLUSIONS: <br />LIMITATIONS: <br />Praneet R Erusu, P.E. <br />Principal Engineer <br />Erusu Consultants US Inc. <br />The observed roof framing is described below. If field conditions differ, the contractor shall notify the engineer <br />prior to starting construction. The roof framing is supported by 2x4 Trusses @ 24" O.C are spanning between <br />load bearing walls. The maximum allowed clear span of 2x top chord member between panel points is 9ft, to be <br />verified in field by the contractor. <br />Based upon our review, we conclude that the existing structure is adequate to support the proposed solar panel <br />installation. In the area of the solar array, other live loads will not be present or will be greatly reduced (2019 CBC, <br />Section 1607.13.5). The gravity loads and the stresses of the structural elements, in the area of the solar array are <br />either decreased or increased by no more than 5%. Therefore, the requirements of Section 503.3 of the 2019 <br />CEBC are met and the structure is permitted to remain unaltered. <br />We conclude that any additional wind loading on the structure related to the addition of the proposed solar array <br />is negligible. The attached calculations verify the capacity of the connections of the solar array to the existing roof <br />against wind (uplift), the governing load case. Regarding seismic loads, we conclude that any additional forces will <br />be small. Conservatively neglecting the weight of existing wall materials, the installation of the solar panels <br />represents an increase in the total weight (and resulting seismic load) of 1.9%. Because the increase in lateral <br />forces is less than 10%, this addition meets the requirements of the exception in Section 503.4 of the 2019 CEBC. <br />Thus the existing lateral force resisting system is permitted to remain unaltered. <br />Installation of the solar panels must be performed in accordance with manufacturer recommendations. All work <br />performed must be in accordance with accepted industry-wide methods and applicable safety standards. Existing <br />Roof and structural members are assumed to be in good and serviceable condition. The contractor must notify <br />Erusu Consultants US Inc. should any damage, deterioration or discrepancies between the as-built condition of <br />the structure and the condition described in this letter be found. Connections to existing roof framing must be <br />staggered, except at array ends, so as not to overload any existing structural member. The use of solar panel <br />support span tables provided by others are allowed only where the building type, site conditions, site-specific <br />design parameters, and solar panel configuration match the description of the span tables. The design of the solar <br />panel racking (mounts, rails, etc.) and electrical engineering is the responsibility of others. Waterproofing around <br />the roof penetrations is the responsibility of others. Erusu Consultants US Inc. assumes no responsibility for <br />improper installation of the solar array. <br />05 Jan 2023 <br />EXP : 30 Sep 2023 <br />2102 W Moore Ave <br />01/30/23