I recently removed a closet in our main living area and one of the closet walls contained an AC supply vent. This left a 4x12 hole in the floor where the old stack head was removed. While we could just buy a flush floor register cover before our floors get refinished tomorrow, I'd rather relocate the vent in the remaining wall next to the previous vent location.

I measured between the remaining closet wall studs and I'd have enough space for a 4x10 stack head (so a bit smaller than the old one). This leaves me with a couple of questions:

  1. Can I trim the circular ducting beneath the subfloor back so I can fit an end register duct boot to the new location? Or do I need to replace the existing ducting with a shorter length and then attach the end register boot?
  2. Will it cause issues if I relocate the outlet in that space to the opposite side of the stud it's currently attached to to make room for the new vent, or is placing an outlet that close to an AC register a bad idea?

Here's a view of the removed closet and old vent location/proposed new vent location (the area w/ the wall knocked out and outlet exposed.)

Here's a view of the duct from the basement. I'd like to trim it back to the left side of the pipe and electrical wire, if possible.


1 Answer 1

  1. Yes, you can shorten the duct as needed. If you need a crimped end to fit the new boot, a needle-nose pliers from the end and a bit of twist will create that for you.
  2. If you're not running full ducting*, you'll need to either relocate the outlet or box around it with lumber so that it's not technically in the same cavity as the duct flow. Use silicone or some other fire-resistant caulk to seal the holes in the studs.

* Modern code may require full fire-resistant ducting for supply vents.

  • Perfect. I've tackled several other projects in this house, but working with ductwork is new to me. The house was built in the 50's and I'm sure the ductwork fairly old as well. Is there a specific kind of tin snips you'd recommend to cut back the duct or will most snips off the shelf suffice for this job? Aug 4, 2020 at 20:38
  • 1
    You'll have a heck of a time getting snips in there. I'd try a cutoff wheel in a rotary tool from the inside. Otherwise, a standard snips is fine. The sharp-point ones are more versatile. Please take the tour so you know what to do next. Feel free to wait for more answers.
    – isherwood
    Aug 4, 2020 at 20:50

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