Screws that normally fix the vent in place can't do their job anymore. The drywall has crumbled to the point that the tapped hole for the screw lacks a boundary with the duct. (Picture attached.)


  • The cutout for the original vent larger than necessary, forcing the screws to be closer to the duct than is optimal?
  • The original installation should have used some sort of plug so that the threads of the screw didn't compromise the integrity of the drywall so easily?

How would you:

  • (a) go about fixing this?
  • (b) prevent this from happening in future installations?

The issue, in an image:

Vent hanging partway out from ceiling

  • 5
    Those screws should be screwing into the metal of the register box behind the drywall, ans not relying on the drywall itself for any holding strength.
    – brhans
    Jun 12 '17 at 13:59
  • 3
    The one that's still holding is probably into a joist. Use a single 3" screw and forget 'bout it. Also, that's a floor register.
    – Mazura
    Jan 22 '19 at 14:32

My default fix would be just to put in some type of anchor. Given the damage and the fact this is on a ceiling, I'd be inclined to use a screw-in type anchor, because they hold on to a larger area and would deal better with some damage.

enter image description here

If that couldn't work, the next thing I would look at would be getting a new surface to screw into.

Normally the method is to use a backing board, which is basically just a small piece of wood -- perhaps 3/4" x 2" x 4" -- to screw into on each side. Unless the vent can be moved easily, this will be difficult.

In this case I'd actually construct some "wings" using some sheet metal to wrap around and over top of the drywall, which the vent would then screw into. They'd anchor into the vent itself.

enter image description here

  • 2
    Wonderful - thank you for the advice. Really appreciate it. The visual component leaves me with 0 clarifying questions! I'll see if I can make any use of the plug/anchor before I go making wings. Jun 12 '17 at 14:06

I got a tip elsewhere about using JB Weld, as I had the same problem. Worked like a charm! I got the one made for wood. It was a putty stick. You knead it together then stuff it into the screw hole. It hardens in 1 hour and gives you a fresh surface to drill a new hole. Good luck!


If this is a heating duct, place a piece of sheet metal on the other side of the drywall and use a self-drilling screw to reattach the cover. If this is just a cover over a ventilation hole to the next floor (somewhat common in older buildings), you can safely use a piece of wood instead.


I had the same problem in my basement, as well as for a few clients (I'm a handyman). I came up with a spring system to hold the vents in place. Here's a link to the video I created for it. It's not dependant on the drywall holding anchors, or any screws of any type.


  • 2
    Welcome. That's pretty cool, but answers should be self-contained--not depending on external resources like YouTube. Maybe add some still shots from the video and a brief explanation of the repair technique.
    – isherwood
    Mar 18 '20 at 17:34

How about getting springs and drill small holes for the springs at the end of the vent's inner frame and corresponding holes in the metal duct high enough so you can attach the springs while pulling down but where the springs also pull the vent up into place afterwards. Just like some recessed light housing covers that are held up with springs.

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