Roof Curb Coordination Guide
How to review roof curbs for rooftop equipment, structure, flashing, insulation height, roof slope, drainage, and maintenance access.
Roof curbs support rooftop units, exhaust fans, skylights, hatches, duct penetrations, and other roof-mounted items. They also interrupt the roof assembly, so they must coordinate with structure, flashing, insulation, drainage, and maintenance access.
A curb that fits the equipment can still fail if it is too low for insulation, lands between structural supports, blocks drainage, or conflicts with warranty details.
Coordination Checks
Review roof curbs on the architectural roof plan, structural framing plan, mechanical roof plan, equipment schedule, and roofing details. Each drawing carries part of the requirement.
- Curb size, height, slope correction, and equipment orientation.
- Structural support, opening framing, and concentrated loads.
- Flashing height, counterflashing, membrane tie-in, and warranty requirements.
- Insulation thickness, cricket layout, drainage path, and ponding risk.
- Service clearance, fall protection, and safe walking routes.
Common Problems
Common roof curb misses include curbs ordered before final equipment selection, curb heights that do not clear tapered insulation, ducts that do not align with openings, and curbs placed too close to parapets or drains.
Helonic helps flag these conflicts by comparing the roof and MEP drawings that are often reviewed separately.
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