Component and Cladding Wind Loads for Soffits

The wind induced failure of soffits of low rise structures is a failure mechanism commonly observed in post hurricane damage investigations. The failure of the soffits has the potential to allow both wind and water to enter the attic space of the building. The current US national wind loading standard (ASCE 7) provides no guidance as to the wind load requirements for the design of soffits. In order to address this deficiency, wind tunnel tests on 1:50 scale models of one-, two-, and three-story hip and gable roof buildings were performed where measurements of the wind induced pressures and suctions on the soffits, roofs, and walls were obtained. The wind tunnel tests were performed in open and suburban terrain conditions, with and without surrounding buildings in place. The results of the tests clearly show that the soffit pressures are nearly fully correlated with nearby wall pressures, and a simple and accurate solution to the soffit loading deficiency in ASCE 7 is to prescribe that the component and cladding pressures for use in the design of soffits be identical to the component and cladding loads used for the design of wall components.