Equipment is part of the structure
ASCE 7 includes provisions for wind forces on rooftop structures and equipment. These forces can be significant, particularly near roof edges and in coastal areas with higher design wind speeds.
Anchorage and load path
Curbs, rails and anchorage must transfer uplift and lateral forces into the roof framing. Manufacturers often provide certified curbs, but the supporting structure still needs to be checked for the reactions.
Equipment weight also matters. Replacing an older unit with a heavier one can exceed the capacity of existing joists, which is why capacity checks are a routine part of renovation work.
Coordinating early
When mechanical and structural engineers select equipment locations together, framing can be sized once and openings placed where they work for both disciplines.
This article provides general information only. Project-specific design requires review by a licensed engineer, and code editions vary by jurisdiction.
