Can i leave existing drywall alone when adding two small walls to a finished basement?

Question

I am building two small walls in a finished basement to create a enclosed landing at the bottom of the stairs.

The new walls will meet at 90 degrees, both will be coming off studs in the existing walls.

The new walls are each about 4' long, one has a doorway.

Thing is i'd rather not cut the finished drywall on the existing basement walls and ceiling. I can locate studs and joists for where the new walls will attach,and i'm anchoring the walls solidly to the cement floor.
I will use long deck screws to anchor the top plates and end studs to existing framing (to get through 1/2 inch drywall) Neither new wall is load bearing, but one will have a door in it so its important that the structure is solid.

My Question: Does leaving the drywall on the ceiling and existing walls significantly weaken the integrity of the new structure?

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Follow up:

Thanks for the answers everybody!

i think the threshold will be fine im going to put 2 pre-drilled concrete anchors through the bottom plate on either side of the base plate.

After serious consideration, I think I'm gonna leave the drywall on. I understand all the reasons for taking it off, but I'm confident that between the shearing strength of all my heavy screws and the very solidly attached bottom, the walls will be sturdy enough for my purposes. Even the force of a seriously slammed door is dissipated over the entire two wall system.....hopefully:)

Answer 1

You could but why would you?

You are going to have to mud/tape your corners whether you take the drywall out or not. It will take you no more than 10 mins to dremel or knife out those two tiny sections of drywall.

Why you should:

1. You can see things easier.
2. You aren't relying on drywall for wall structure. I know this wall shouldn't be supporting anything but any weight at all will crush drywall.
3. Your nails or screws will not be binding to anything for 1/2-3/4 of an inch.
4. You will not be able to frame really tight unless you crush the drywall.

Points 3&4 could lead to a wobbly wall. Think of taking a big couch down in this basement. Corner of couch hit door frame hard. You don't want the top moving.

Answer 2

To answer your question "does leaving the drywall on the ceiling and existing walls significantly weaken the integrity of the new structure?" directly, the answer is "yes". Couple of reasons:

• Take a couple scraps of 2x4s and put a 1/2 inch spacer between them. Screw them together with your decking screws without going through the spacer, and then remove the spacer. You'll find that it doesn't take a lot of force to rotate them against the screws. This is essentially what you'd be doing - except there'll be a piece of sheet rock between them crushing every time the door opens and closes.
• A 32" door in a 53" wall is going to leave less than a foot on each side to anchor the floor plate to. That means at most 2 anchors on each side if you can keep them from splitting when you fire a power actuated nail through them. Keep in mind that a wall this short really isn't much of a "wall" structurally - it is mostly a hole to fit the door into. Keep in mind that the bottom of the door is where the wall will get the most stress - there isn't a jam running across the floor to distribute it.
• On top of that, the door isn't going to stay closed all the time, and it will get slammed shut a couple of times. This is going to put forces into both of your new wall sections that don't have enough space to dissipate before they get to the existing walls/ceiling.
• The ceiling joists only run in one direction. You'll be limited in placement of the wall with the door in it because you'll need at least 36" inches of landing to comply with code (and for obvious safety reasons). That means you'll likely have to block in at least one direction to secure the top plates of the walls.
• Since you'll be rotating the studs in between the plates and likely have to do this with a hammer if they're fit well, you'll be crushing the drywall on the ceiling as you plumb them because there's no give in the floor at all.

You can certainly build a wall this way, but the question is why you would want to. Taking out a bit of sheetrock isn't difficult at all - you'll already be taking off the baseboard, and on the ceiling you'll find it a lot easier to blend the texturing into the new work if you have an extra foot or so to work with.

Regardless of what you end up doing, I'd suggest taping the joints with fiberglass tape instead of paper. It will help protect against the door cracking the seams.

Answer 3

If you have studs attached to the existing wall and those studs are attached using long enough screws to attach to the studs behind, that's perfectly fine. In fact, removing the existing drywall will cause more problems than not.

edit: my answer is clunky: just screw the new studs right on top of the existing drywall into the wall studs behind the drywall.

The bigger problem is usually what to do with the threshold...

Answer 4

There is no problem with attaching through drywall. The L shape will make it very strong. while it would not be hard to remove the drywall you will then have in install nailers for the existing drywall. Not huge project but still an unnecessary one. Double the top plate to overlap the corner. One side will not have a floor joists to attach too so you need a strong corner. I would go right over the carpet too. Use tapcons screws

Answer 5

The most you need to open up is the ceiling since the joists run the same direction as the wall that the door is on, You will need to add blocking between the joists to control the top plate. Since the bottom plates will be short and prone to splitting easily, predrill and use concrete screws as mentioned by Justin, below. A good grade of construction glue under the plates is what I would do too. This will keep them in place for the long haul. The stud against the wall only needs to be set in a bed of caulk or construction adhesive and set tight to the wall. I have used this to hold trim in place when no nailing was available, and I had need to remove a piece after I installed it and when I did, CHUNKS of drywall came with it. It was really tough to remove, but it was set in a full bed caulk. This location can handle it, since the door is not working directly off it, it will be on other studs separate from that one. You may also find a block in the wall mid way up and fasten to that, that would be handy.