Exposed spiral with linear diffuser
Architectural air-distribution assembly
Before you start
- Confirm diffuser length, slot location, room-axis alignment, factory saddle or boot, duct seam location, hanger clearance, support against rotation, and required internal sealing.
- Field-check the diffuser line from the room below before cutting the duct.
- Verify the cutout will not cross or weaken the spiral seam, bead, joint, or support point.
- Stage the factory connection, layout template, cutting tools, reinforcement if specified, sealant, and rotation-resistant supports.
Tools and materials
Exposed spiral duct, approved linear diffuser and factory saddle or boot, layout template, laser, level, marker, approved cutting tools, deburring tools, fasteners, sealant, rotation-resistant hangers, clean gloves, and interior-cleaning supplies.
Lay it out
- Laser the diffuser centerline to the room or architectural axis.
- Transfer the exact opening and fastener pattern to the duct.
- Check seam, hanger, fitting, and joint clearance before cutting.
Set and support it
- Support the spiral duct on both sides of the diffuser assembly.
- Use supports that resist rotation caused by the diffuser weight.
- Level and lock the duct before cutting the opening.
Make the connection
- 1
Verify the layout from below and mark the final opening.
- 2
Cut accurately while supporting the cookie so it cannot fall into the duct.
- 3
Deburr and clean the opening.
- 4
Set the factory saddle or boot square to the duct and room axis.
- 5
Mechanically fasten the connection evenly.
- 6
Seal internally or neatly as the approved detail requires.
- 7
Install the diffuser and recheck level, alignment, and duct rotation.
Check the install
- The diffuser line is straight and aligned with the room.
- The opening is clean and does not damage the spiral seam.
- The duct remains round and does not roll.
- The saddle or boot is fully seated, fastened, and sealed.
- No debris or cookie remains inside the duct.
Common mistakes
- Cutting before checking the view from the room below.
- Allowing the cookie to fall into the duct.
- Locating the opening across the spiral seam or too close to a hanger.
- Installing the diffuser before the duct is braced against rotation.
Stop and ask
Stop if the opening weakens the seam, conflicts with a hanger or joint, the diffuser line is not coordinated, or the duct cannot be supported against rotation.