By B. Kevin Folsom, CEP
Published in the November 2012 issue of Today’s Facility Manager
Q We have instances of leaks at the metal roof to HVAC curb on a minimum 2/12 sloped roof. Because the International Building Code (IBC) requires the equipment to be supported against any seismic action, the HVAC equipment must not move with the roof plane. The metal roof plane can expand and move approximately 3⁄4″ from the bottom edge to the top ridge. Do you have any recommendations for flashing this HVAC unit? Is a double curb the only way to approach this situation?
A Roof leaks always find their way to the detail areas. This is where real roofing skill is needed along with close attention to detail. An organization I have found to be very useful over the years is the National Roofing Contractors Association (NRCA). I have even sent staff members to its roofing institute. My advice would be to submit your question to this page. Even if you had to pay a fee, it would be worth it. Never underestimate the importance of a roofing system and don’t take short cuts. I almost always use an independent building envelope design consultant for new and replacement commercial roofing. [Read more about roof maintenance strategies here.]
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