Evaluation of Existing Buildings for Feasibility of Photovoltaic Array Installation

Installation of PV arrays on existing roofs and/or façades imposes additional loading onto buildings with implications for the performance of the gravity and lateral structural systems. For solar projects that begin with a feasibility assessment, it is recommended to perform a field investigation followed by structural evaluation. The field investigation typically includes visual observations, non-destructive testing (NDT), such as ground penetrating radar (GPR), and/or destructive exploration. The structural evaluation includes performing calculations to determine the loading and capacity of the existing gravity and lateral structural systems to support the additional PV loading. Best practices for documenting existing structural information from limited field investigations are presented. Methods for performing feasibility-level structural evaluations are outlined. Case studies are presented to illustrate the feasibility assessment procedure considering two different existing buildings. The general procedure is shown to effectively allow for the determination of the feasibility of PV array installation using a combination of strategic field investigation and structural evaluation.