What weight can heavy asphalt shingles with multiple layers approach per square?

Heavy asphalt shingles, especially when installed in multiple layers, typically approach a weight of around 500 pounds per square. This weight is important for home inspectors to consider as it can have implications on the structural integrity of a roof. Understanding the load that roofing materials impose on a structure is crucial, as too much weight can lead to various structural issues, including sagging or, in extreme cases, failure.

When heavy asphalt shingles are installed, they generally include both the weight of the shingle material itself and any additional weight from overlapping layers. The cumulative weight of these shingles necessitates proper evaluation of the roof framing and supports to ensure they can bear this load without compromising the building's safety. Inspectors need to be aware of these weights for accurate assessments and recommendations to homeowners or clients regarding roof maintenance and any imminent concerns.