Inspect and correct the damaged flange before assembly: flange damaged during material handling. Bent rails/corners can prevent gasket compression and create leaks.
In Rectangular Duct Assembly: TDC / Ductmate / Flanges, I’m looking at: What do I do when flange damaged during material handling? What should I verify before I cut, drill, seal, cover, move, or install?
Do not
Do not force a damaged flange together and bury the issue.