Exterior Duct Joint or Support Creates a Water-Catching Low Spot

Fast answer

Verify the exterior duct elevation, support arrangement, joint orientation, weatherproofing system, and intended drainage before adding sealant or randomly lifting one hanger. Correct the cause without damaging the approved support or exterior insulation system.

What to check

1. Measure the low spot from stable roof or structural references.
2. Check whether the duct, outer jacket, flashing, or support is creating the pocket.
3. Inspect nearby seams, penetrations, and insulation for water entry.
4. Confirm the approved adjustment and weatherproofing repair.

Do not

Do not drill a drain hole, crush insulation, or change roof supports without approval.

Ask the foreman

“This exterior run has a measured low spot holding water at the joint. I checked the adjacent supports, jacket, and roof pitch. Do you want the support elevation corrected, the exterior assembly reworked, or the condition reviewed against the approved detail first?”

Why it matters

Standing water attacks seams and coatings, loads the exterior jacket, finds small defects, and can become a recurring leak.