From the Benchmark Blog:

Benchmark Service: Construction Phase Services

Issue: In the process of removing an existing roof curb, the roofer did not realize the duct seams were not sealed and air was escaping from the gap. This duct leak was located below the level of the new roof curb he was installing.

Solution: The Benchmark Field Consultant instructed the roofer to pause the installation of the new roof curb and seal the duct seams with sealant tape to make the joint airtight.

Possible Impact: This condition would have resulted in air being forced under the new roofing system, potentially causing moisture and pressurization issues that may have resulted in premature roof failure, not to mention reduced HVAC performance to the client.

Learn more about Benchmark from their RCS Directory Or visit their "Observations from the Field" blog.