Impact of heavy snow accumulation on roof serviceability

Over 100 buildings were examined which had damage or indications of distress due to an unusual accumulation of snow in north-eastern USA during the winter of 2010–2011. Approximately 40 of those buildings had a partial or total collapse. Records of the amount of snow that accumulated on roofs in the region were collected and compared to snow-load requirements in building codes over the past few decades. Buildings were evaluated and causes for distress identified, as well as emergency actions that needed to be taken when appropriate, mitigation strategies and repair concepts and repair documents when necessary. This paper explores the snow loading environment of the 2011 winter in north-east USA, describes three case studies with financial costs due to roof deflection, and provides recommendations for designers, building owners and occupants on how to minimise such collateral costs under similar circumstances.