Joining Rectangular Duct With Metal Cleats

Written by elizabeth knoll
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While installing round duct together simply requires sliding the male end into the female end and securing with sheet-metal screws, a little more work is involved with joining rectangular duct. Rectangular duct involves S-slips and drive cleats. The S-slips have pockets that allow the raw edges of the rectangular duct to join. Then the connection is held together with drive cleats. At first, you may find connecting rectangular duct somewhat challenging, but once you get the hang of it, you should be able to connect a rectangular joint about as fast as connecting a round joint of duct.

Skill level:
Moderately Easy

Things you need

  • Tape measure
  • Snips
  • Flathead screwdriver
  • Hammer
  • Heavy-duty leather gloves

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  1. 1

    Look at the end of your duct. Of the four sides, two will have raw edges, and two will have hemmed edges. The raw edges are where the S-slips slide on, and the hemmed edges are where the drive cleats slide up to hold the joint together.

  2. 2

    Cut your S-slips and drive cleats for the duct connection. Cut two S-slips a half inch shorter than the length of the raw edge. Cut two drive cleats 2 inches longer than the length of the hemmed edge.

  3. 3

    Tap one S-slip on to raw edge of the duct you will be connecting to. Use a screwdriver to slightly open one end of each drive cleat. This will make connecting the two ducts slightly easier.

  4. 4

    Connect the two ducts. Insert each raw edge of one duct into S-slips you installed in the previous step. Push the two ducts together until the hemmed edges butt up tight to each other.

  5. 5

    Slide a drive cleat on to one side of the duct, and tap it all the way up with your hammer until 1 inch is sticking down below the bottom of the duct and 1 inch is sticking up above the top of the duct. Repeat the process for the other side.

  6. 6

    Tap the drive cleats over on both the top and bottom of the duct. The two ducts will now be locked together.

Tips and warnings

  • Seal all seams of S-slips and drive cleats with duct sealant when complete. Seams of rectangular duct can leak large amounts of air if left unsealed.
  • Wear heavy-duty leather gloves when working with ducts. The sharp edges will cut your unshielded skin.

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