Question about drywall and reveal at windows

[David250]

Thanks for all the great answers and I'll continue with a new question on the same theme.

Attached in the picture, you can see the whole short side on the upper floor. It will be divided in the middle where the area to the right of the green line will be a workspace and to the left a bathroom.

A partition wall will of course run between them (symbolized by the green line). However, there is no stud where the green line is marked.

How should I proceed to plaster the blue area? Can I place a board that covers the entire blue area plus a little over the windows, or do I need to use different pieces and install a stud in the middle of the blue area since to the left is a bathroom? The bathtub is to be placed in this corner, otherwise, perhaps it wouldn't matter as much?

 

[MoN]

If I were you, I would have put a layer of OSB on the outer wall, then framed the inner wall and put OSB on this one as well. After that, I would have screwed metal brackets in the joints between walls and floor, walls and ceiling, and between the outer wall and inner wall. This is to prevent movements in the joints where there is the greatest risk of moisture damage. After that, you gypsum the walls.

 

[David250]

If I were you, I would put a layer of OSB on the outer wall, then frame the inner wall and also put OSB on it. After that, I would screw metal angles into the joints between walls and floors, walls and ceilings, as well as between the outer wall and the inner wall. This is to prevent movement in the joints where there is the greatest risk of moisture damage. Then you gypsum the walls.

Thanks for that input, not a bad idea with OSB first so you can then put gypsum on each side. However, the wall becomes slightly too thick.

I have tried previously for another part of the room to get metal angles to attach the gypsum. However, I was informed by the building supply store that it was no longer in demand, so they didn't have it. They thought you could use an extra wooden stud instead.

Then just to double-check, you mean metal in the joints in the bathroom? In the bedroom, it probably isn't necessary, right?

 

[MoN]

That's right, it is needed in the bathroom.

I would have continued to look for the metal brackets. Here in Uppsala, it's no problem to get hold of these at, for example, Woody. If you add an extra wooden stud, you won't eliminate the movements since it will also move due to moisture. Länsförsäkringar encourages (at least here in Uppsala) that these metal brackets should be installed.

 

[David250]

That's right, it's in the bathroom where it's needed.

I would have continued to look for the metal brackets. Here in Uppsala, it's no problem to get hold of these at, for example, Woody. If you add an extra wooden beam, you won't eliminate the movements because it will also move due to moisture.
Länsförsäkringar encourages (here in Uppsala at least) the installation of these metal brackets.

I will do that, the funny thing is that it was at Woody here in Falkenberg where I got the answer above.