I'm looking at adding a hollow-core door across a finished hallway. On one side of the hall, there's already a stud inside the wall where I intend to install the door. This would be the hinge side of the door. The other side of the hall does not have a stud that aligns with the lock-side of the door. It does, however, have 2 layers of 3/4 inch drywall.

Can I build a rough opening for the door on the outside of the hallway wall even though there is no stud on the lock-side of the door? If I use toggle bolts to secure a stud to the surface of the drywall, would this be adequate for the framing of this door?

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  • Why so thick with the drywall? is this a firewall?
    – Jasen
    Commented Nov 17, 2020 at 19:19
  • @Jasen This happens to be a shared wall in an apartment-style condo. I imagine the double drywall is to help will sound-proofing.
    – BahKoo
    Commented Nov 18, 2020 at 20:51
  • That sounds like a firewall to me. you don't want to go cutting holes in that.
    – Jasen
    Commented Nov 18, 2020 at 20:59
  • @Jasen Thanks for the heads up. I will run this by my condo board before doing anything. If this is a firewall, do you think there's any way to safely install a door here? The wall does have several outlets installed already. Doesn't this mean that wall already has holes?
    – BahKoo
    Commented Nov 19, 2020 at 1:43

2 Answers 2


Even with a light weight hollow core door, there should be framing or something to keep the strike side stable while the door is closing against the jamb. Otherwise the slight vibration by using the door may cause the inside corners to crack. What I do is cut out a section of drywall from behind the area that is covered by the new wall. If the new drywall added to the new wall will have the inside corners taped and finished, it give a lot more room to work with, since the wall is getting mudded anyway.

The cutout section would be in the middle of the height of the wall, a slot cut out about 2' tall and in you case about 4" to 5" wide if you are finishing the corners. With the cutout made, insert 2 pieces of 3/4" plywood approx. 6 or 7" wide by slightly shorter than the height of your cutout. With the cutout in the middle of the wall, slip the first piece plywood in the hole so the bottom is in the middle of the hole, centered left to right over the cutout. Using screws that are long enough, secure the first piece in place through the drywall above the cutout, using a screw set into the face of the plywood to serve as a handle to hold the plywood firmly while the first few screws are set. The second piece of plywood will be set in the same way below the first one you set. By the way, you may need to set the 2nd piece in the hole first since the hole may be too small to go in after you set the first piece.enter image description here

After the plywood is secure, you can reset the original drywall back in the hole and secure it place with a screw or 2 to act as filler since the long screws that will hold the studs in place will sandwich it all together anyway.


When cutting drywall, only cut as deep as needed to make the cut all the way through. There is no way to know where wire or pipes that may be in the way of your cut path. You may make a small "inspection hole" about 6" tall to get a literal feel what is inside the wall before cutting any farther.

  • Thanks for the detailed explanation of your technique. Just to make sure I understand correctly, your solution does not require adding a stud inside the wall on the on the strike side of the door. In a sense, you are using plywood and screws almost like a giant toggle bolt that will help keep the new stud in place. Is this correct? Is one of these holes sufficient or would it be better to have 2?
    – BahKoo
    Commented Nov 16, 2020 at 4:42
  • this wall is a fire barrier, this modification will not meet code.
    – Jasen
    Commented Nov 18, 2020 at 21:04
  • Yes, your description is accurate, in this case a very strong toggle bolt. There will be no holes after everything is covered back up using the plugs of drywall that can go back in the holes. Again as I mentioned above, if this wall needs to be fire rated you will need to rethink you entire wall system.
    – Jack
    Commented Nov 19, 2020 at 3:43

Don't use a wooden stud, use something stronger like rectangular hollow steel and fix it securely to the top and bottom plate.

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