Structural Design Requirements for Solar Installations
Breadcrumb: Home > Permitting & Development > Structural Design Requirements for Solar Installations
Source: Structural Design Requirements for Solar Installations ↗ Last modified: Sun, 19 Apr 2026 20:04:03 GMT
Dead and Live Loads
The solar installations and their supporting structures shall be designed following section 1607.14.4 of the Oregon Structural Specialty Code ↗ (OSSC). The self-weight of the photovoltaic panels and modules and ballast (if any) shall be treated as dead load. Roof Live load shall be determined per section 1607 of the OSSC. You may submit questions about this page ↗ online.
Snow Loads
Snow loads shall be based on section 1608 of the OSSC. Snow load on the photovoltaic panels shall not be taken less than 20 psf x Importance factor is. following section 1608.2.3 and 1608.2.4 of the OSSC. Snow drift created by the photovoltaic installation shall be considered.
Following section 1607.14.4.2 of the OSSC the structure of the building supporting the photovoltaic panels or modules shall be designed to accommodate the full solar photovoltaic panels or modules and ballast dead loads, including concentrated loads from the support frames in combination with the loads due to live loads, snow, wind and seismic. Load combinations shall be per section 1605 of the OSSC.
The structure of the roof that supports the solar photovoltaic panels shall be designed to accommodate the full solar photovoltaic panels and ballast dead load, including concentrated loads from the racking support or standoffs due to all applicable dead, snow and wind loads
When designing the supporting roof framing for loads including roof live loads, snow loads, or wind loads, the supporting structure must be designed for the following two conditions per section 1607.14.4.1 of the OSSC (1) all applicable dead, snow and live loads assuming the photovoltaic panel system is not present and (2) the applicable dead, live, snow and wind loads including any concentrated loads from the photovoltaic panel system from the racking support or standoffs. Roof live loads applied to the area covered by photovoltaic panels where the clear space between the panels and the roof surface is 24 inches or less need not be considered in this case.
Wind Loads
The design wind loads for solar photovoltaic arrays shall be based on the latest edition of the OSSC and American Society of Civil Engineers (ASCE) 7 ↗. The following methods may be used to determine the wind loads on solar arrays:
- Wind loads determined in accordance with sections 29.4.3 and 29.4.4, or 30.13 of ASCE 7;
- Wind load determined following Wind Tunnel tests per OSSC section 1609.1.1, ASCE 49, and Chapter 31 of the ASCE-7;
- For low-profile solar photovoltaic arrays on flat roofs, use the Structural Engineers Association of California (SEAOC) Report PV2-2017, Wind Design for Solar Arrays.