Install a basic S-and-drive joint

Before you start

• Confirm the duct size, end construction, pressure class, seal class, and joint shown on the approved shop drawing.
• Inspect both duct ends for crushed corners, torn locks, bowed panels, loose reinforcement, or shop damage before lifting them into place.
• Make sure the supports are already installed or the sections are otherwise held so the joint is not carrying the weight of the run.
• Stage the correct S-cleats, drive cleats, sealant, hand tools, clamps, and access equipment before starting the joint.

Lay it out

1. Use the bottom or top plane of the installed run as the reference. Do not line up only one corner and assume the rest of the duct is correct.
2. Check that the two sections are the same size and that the male and female lock edges face the right direction.
3. Position the joint where both side drives can be installed and inspected. Shift the piece breakdown before installation if a wall, beam, or other trade blocks a drive.

Set and support it

1. Set both sections on their hangers or temporary supports and bring them to the same elevation.
2. Keep the upstream section stable. Raise or lower the loose section until the bottom panels and side corners meet without one piece hanging from the other.
3. Use a clamp or duct stretcher only to hold correctly sized pieces in alignment—not to pull a wrong-size or twisted section into place.

Make the connection

1. 1

   Slide the S-cleats onto the top and bottom edges. The cleat must capture both duct hems for the full width of the joint.

2. 2

   Bring the sections together evenly. Watch all four corners so one side does not enter while the opposite side rides outside the lock.

3. 3

   Square the duct before installing the drives. Check the bottom plane, side walls, and corner alignment from more than one angle.

4. 4

   Start each drive over the folded side edges by hand. If it will not start, stop and correct the edge rather than beating the drive onto a damaged lock.

5. 5

   Drive each side cleat fully and evenly. Alternate attention between sides so the joint does not rack while one drive is seated.

6. 6

   Secure or fold the exposed drive ends in the approved manner and remove sharp projections.

7. 7

   Complete the required joint seal after the mechanical connection is correct. Do not use sealant to hold together a loose or incomplete joint.