Missing gasket overlap at corner

Keep the gasket continuous through the corner on one flange face. Do not stretch it to reach, leave a gap, or put gasket on both duct ends.

Rectangular Duct & Fittings 2nd Year YELLOW

Stop if

Ask when connector type, gasket, cleat/bolt schedule, pressure class, or manufacturer detail is unclear.

Watch out

Do not double-gasket, stretch gasket thin, mastic over a gap, or use corner hardware to pull a crooked joint shut.

Check

Open the joint enough to see the full corner.
Replace or re-seat gasket so it stays relaxed and continuous through the corner.
Bring the joining duct in level and square with corners installed on that duct.
Use drift pins only for close holes and protected clamps only to hold flange faces.
Recheck all four corners before tightening evenly.

Steps

Open the joint enough to see the full corner.
Replace or re-seat gasket so it stays relaxed and continuous through the corner.
Bring the joining duct in level and square with corners installed on that duct.
Use drift pins only for close holes and protected clamps only to hold flange faces.
Recheck all four corners before tightening evenly.

Say this to your foreman

In Rectangular Duct Assembly: TDC / Ductmate / Flanges, I'm looking at: Missing gasket overlap at corner. What should I verify before I cut, drill, seal, cover, move, or install?