S-and-Drive Square Duct · End boot connection

Connect boot with S-and-drive

Rectangular boot

Task typeEnd boot connection
Tools / equipmentBoot support, S-lock, drives

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. Confirm the finished ceiling or wall plane and the exact register/diffuser opening location.
  2. Verify boot orientation, throat direction, collar location, and face size.
  3. Check for framing or backing needed to keep the boot square at the finished surface.

Set and support it

  1. Set the boot at the final elevation and secure it independently to framing or structure.
  2. Hold the face opening square and flush to the finish plane.
  3. Bring the branch duct to the boot without pulling the boot sideways.

Make the connection

  1. 1

    Fit the S-cleats to the boot connection and branch duct.

  2. 2

    Align the branch with the boot throat so there is no step or twist.

  3. 3

    Start and seat the drives while the boot is clamped or supported.

  4. 4

    Finish the drive ends and seal the connection.

  5. 5

    Recheck the boot face after the branch is released.

  6. 6

    Confirm the register or diffuser can be installed and removed.

Check the install

  • The boot face is square, level, and at the correct finish depth.
  • The branch is aligned with the throat and does not distort the boot.
  • The boot has its own support; ceiling grid or drywall is not carrying duct weight.
  • The joint is sealed and the device mounting surface remains usable.

Common mistakes

  • Connecting the branch before the boot is secured.
  • Using the branch to pull the boot to the ceiling opening.
  • Leaving the boot too deep or proud of the finished surface.
  • Crushing the throat while tightening a clamp.

Stop and ask

Stop if the ceiling layout is not final, framing/backing is missing, the boot orientation is wrong, or the branch cannot reach without distorting the boot.