I'm trying to mount a sliding barn door in a room. It has five holes in the rail for the lag screws to screw in to. One of the five holes is directly over an HVAC vent that leads to the upper floor - shifting the rail a couple inches either way still ends up with the hole over the vent.

There is enough room to fit the anchor in between the drywall and the vent but the lag screw would puncture the HVAC vent. Would there be any issue with me puncturing the HVAC vent with a lag screw? It wouldn't be holding up the rail as the other four holes are over studs.

see image attached for further clarificationenter image description here

  • 1
    Would leave it off, it would only be there for looks, since it can't hold weight. Moving it to a stud is the best, even if two are close together/far apart. Attaching a 2x4 or 2x6 across the studs and using that to hold the lag screw is another way.
    – crip659
    Nov 25, 2021 at 19:53

1 Answer 1


Ok you've got 4 lag screws into studs and one screw that can't go into a stud.

Screwing into the duct isn't going to bring any benefit, and has the potential to cause problems.

If the empty hole looks ugly you could perhaps cut the head off the spare lag screw and glue that into the screw hole

Depending on how heavy your barn door is you may need to drill some new screw holes in the rail and screw it to the studs either side of the duct.

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