How much old drywall to tear out when adding a room?

[Stephen Tashiro]

I need to add a small room to an existing dinning room. The new room will be closet to hold a furnace. Where the two walls of the closet meet an existing wall, there are the following possibilities:

1. Leave the drywall on the existing wall.

2. Remove a narrow strip of drywall where the corner stud of the closet meets a stud of the existing wall so the the two studs can be joined directly.

3. Tear out enough drywall from the old wall so the junction between the new closet wall and the old wall can be framed as a corner would be built in new construction - i.e. it would be an arrangement where drywall could be put on both the old and new walls and have wood at the corner so the edge of the drywall on both walls would be supported.

Are there other methods?

As I see it:

Method 1 is simplest, but if someone ever needs to replace the drywall on the old wall, they'd face a non-standard situation where the old and new walls meet.

Method 2 leaves the edge of the old drywall at the corner unsupported.

Method 3 is most pleasing to me, but is it worth it?

[Jim Becker]

I'd do either #2 or #1 in that order...structurally, #2 is better because you're fastening wood to wood rather than having drywall between them. Drywall can compress. "Practically" it might not matter, but...

I wouldn't do #3 unless there was another good reason to remove more drywall, creating a bigger mess and more work. Drywall and subsequent mud work is a "thankless task" for most people. I know how to do it well, but I loath the job, itself.

[Adam Herman]

1. all the way. you will loose more shear strength in the wall by cutting it out than you will loose in fastening the 2x over it. drywall really stiffens the structure of a house.

[Paul F Franklin]

When I do this, I cut the sheetrock where the new wall will be framed, and then slip sheetrock corner clips on the cut edge of the sheetrock before framing the new wall. Once I have a stud at the junction, I fasten the corner clips to the new framing.

You can also often tuck and toenail or toescrew a new stud into the cavity so it both supports the edge of the old sheetrock and gives you a solid place to attach the new wall framing. But if there is wiring and insulation in the wall, the clip is the way to go.

[Tim Bueler]

# 1. None of it is structural and cutting out less drywall also cuts out a certain amount of mess. IF someone does have to replace the old drywall at some point it would likely be a full blown remodel or another situation where the problems are bigger than a little drywall behind a closet stud (which MAY also end up being removed at the same time).

I came across the "drywall behind a stud" (or shiplap, or lath & plaster, or ...) situation a number of times in my career. It was no big fizz. By the time we got to that point it was the least of our problems.

[John K Jordan]

I recently did this and left the old drywall. If the place where joined already has a edging strip or is taped you might get a flatter wall by removing that, being careful there is enough support under the new edge of the old drywall. But I'm not sure I understand exactly. It might be easier to understand your situation if you drew a diagram of the existing framing and drywall with the update sketched in.

[Jim Becker]

# 1. None of it is structural and cutting out less drywall also cuts out a certain amount of mess. IF someone does have to replace the old drywall at some point it would likely be a full blown remodel or another situation where the problems are bigger than a little drywall behind a closet stud (which MAY also end up being removed at the same time).

I came across the "drywall behind a stud" (or shiplap, or lath & plaster, or ...) situation a number of times in my career. It was no big fizz. By the time we got to that point it was the least of our problems.

I don't disagree about the less mess thing and for that reason, just leaving the drywall intact is attractive. That said, there is also value in removing the ~4" strip of drywall so one can accurately ascertain what's behind the exact area that the new wall is going to tie into the existing plane and it's wide enough that it would also permit adding some blocking if required to properly join the new with the old securely and safely.

[lowell holmes]

Keep in mind, if you don't do it properly, you will get to redo it. As an old re-modeler, I would take the wall to bare studs and redo the sheet rock.
It will be a pain, but when you do, it will look right and have no problems.

[Robert Engel]

This is a closet and not a structural part of the wall. Drywall compressing is an non issue.

I would do #1. IMO you're creating a lot more work that isn't necessary for this.

I understand the "right" way is to tear out and create a real corner, but in this situation the "best" way isn't always the "right" way.

Future remodelling I don't see an issue. In fact, if someone is tearing the closet out, they will be glad you did it that way.

I would recommend a "reverse" drywall toggle bolt type anchor to keep the corner stud tight to the existing wall to avoid cracks.

[Jerome Stanek]

We would just butt the stud against the drywall but this was metal studs so you could anchor top and bottom. This was in an office building when we were added offices. Never had a problem.

[Tim Bueler]

Say for arguments sake you don't take out the old drywall and attach the starting stud only at the top and bottom. Then you tape/mud new drywall on the new closet wall into the old drywall on the existing wall (and ceiling). What cataclysmic force is going to tear that apart? It's not load bearing so there couldn't be any shear, tension or compression forces in effect. Even though the new wall isn't "blocked" in by drywall on either side the worst that will likely happen is a hairline crack along the joint, which will likely happen anyhow. Unless you have very rambunctious friends/family of course.

It's prudent to remember that except for the first/last stud where a wall intersects ALL studs in a wall are attached at only the top and bottom. Even where a doorway interrupts that plane, there will be a king stud and a trimmer on either side of the door hole, but there are still attachments at the top and the bottom only and only the king studs extend to the top. Yet, even with the added stress of a door hanging/banging on the opening, this assembly doesn't fall apart without serious outside influence. And don't forget about the many walls that don't attach on the ends. Walls that separate dining rooms and kitchens for example. Or a double entry into a kitchen from a hallway. When was the last time you saw a non-load-bearing wall fall over for improper attachment? When was the first time? I've been a builder/remodeler for over 30 yrs and I've never seen it. I've never even heard of it.

It's also worth noting that there are modern lumber and energy saving techniques being used in new home construction every day. One of those techniques, most often used in Passive Haus and Zero Net Energy construction, is to build the exterior assembly, and any interior load bearing walls, and then drywall that interior. Once that initial drywall envelope is taped the interior, non-load-bearing walls are built and finished out. The most advanced builders in this country are doing this every day as a means of energy conservation and occupant comfort. It's the next progression beyond thermal insulation and double pane windows, IMO.

That brings me to another point about opening up the existing drywall. Air leakage. By cutting out the existing drywall you've just cut yet another hole in your exterior envelope. Maybe it's nothing, then again that may a whole other can of worms you don't want to open.

Very sorry I got so preachy! Doing the "right thing" means something different to everyone, just sayin'. Lot's of good suggestions/opinions here and you must pick what you're most comfortable with.

Cheers!