My duct opening is right next to the wall. I pulled out this old register to replace the baseboards but now I can’t fit it in the opening anymore.

It seems like the existing duct gets in the way when the “fins” of the register are open, so it does not sit directly on the floor, but 1 inch or so above the floor.

Seeking options.


4 Answers 4


You can try one of these:

  1. Move the register opening.
  2. Change the size of the opening so a new register will fit.
  3. Order a custom sized register that will fit your new opening. It won’t match the design of your existing registers, but it’s an easy fix for your new duct opening.
  • I don't see how that register offers custom sizing.
    – isherwood
    Dec 30, 2020 at 16:40

That's a custom cut register to fit so close to the wall; you don't want a new one or you'll just have to do that again (which isn't fun).

The problem is the mangled boot. Straighten it as best you can with some pliers. Then attach it like it's supposed to be with some screws into the flooring/subfloor. Find the corner it likes to sit in, biased to either side. Screw the side in with two screws. Then the hard part: screw it down to the room side (may need a right angle drive, and pilot holes). Or screw it down to the wall side after you slip some wood back there to preserve the clearance from the wall.

When you screw it in make it as flush with the floor as possible. When you go to put the register back, stick it in at a 45 and then slide it sideways as you push it down. That may be all you have to do but the problem will persist, and it won't be as air-tight as it could be. Ideally the boot is taped to the floor which the register will hide.


Measure the opening in the metal duct and buy a register that will fit that opening. There are metal ducts that are 2 1/4" high and 3 1/4" high with widths at 10", 12", and 14", Also, turn the white register over and measure the size of the protruding piece holding the moveable vanes. If that dimension is larger than the metal duct opening then that register will not work. Remember, the protruding piece of the register that holds the vanes has to be able to fit into the opening in that duct. Hope this helps


If i understand correctly the register fit before you installed new baseboard trim and now it the trim is causing a miss-alignment. (My answer is based on that assumption, let me know if that is not correct.)

I would suggest that your best option is to remove the baseboard, put the register back in place then hold the baseboard in place on top of the register and mark on it where the ends of the register are. You will need to trim (cut) a notch in the bottom of the baseboard so when it is on the wall the register will be underneath it (recessed in the notch).

If you cut the notch too shallow/short you will not be able to remove the resister so do some testing before you attach the baseboard to the wall.

  • You could probably also just undercut the baseboard with an oscillating too and piece of scrap flooring or other 1/4" wood as a guide without removal
    – redlude97
    Dec 30, 2020 at 18:20
  • @redlude97 True, but it would not look as clean, The shoulders of the notch would not have 90 degree cuts.
    – Alaska Man
    Dec 30, 2020 at 18:32
  • Thanks for your reply. It’s not an issue with the trim, since previously the register was sitting under the baseboard, and was still fitting when I removed the baseboard. I then took out the register to spray paint it white and want to put it back in the opening, and reattach the baseboard.
    – anon
    Dec 31, 2020 at 20:18

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