partial room within a room wall corners question

[2k4s]

If I'm building a room within an already existing room, but i'm not using the whole room, I just want to build in one corner of the larger room, how do you handle the exposed outside corners of the inside room walls?

It's difficult for me to articulate my question so i made a drawing. What does the construction detail look like in the corners where I've made the red circles? I'm having a hard time getting my head around this? How does sound not "leak" out at the ends of the inner wall on those circled sections?


A little more info: the outer structure is a garage with the OSB and siding and exposed 2x4 stud 16" OC on the inside. My proposed inner room would be a 2x4 wall 16" OC on the North and west walls with double 5/8" drywall. And the South and east walls of the inside room would be a staggered stud (2x6 plate with staggered 2x4s) with double 5/8" drywall on both sides.

[Soundman2020]

How does sound not "leak" out at the ends of the inner wall on those circled sections?

If you do it like that, then the sound WILL "leak out"!

What you actually need to do is to just make your entire inner-room into a single-leaf wall, and build a separate wall around the other two sides of it, that links up with the existing outer-leaf wall, but without touching the inner-leaf.

Like this:

MSM-two-leaf-WallChunk-conventional--NOT-inside-out--one-room--S06.png

That assumes that you are planning ti use conventional construction: if you use inside-out construction, then the inner-leaf walls would face the other way, like this:

MSM-two-leaf-WallChunk-NOT-conventional--inside-out--one-room--S06.png

That's how you do proper fully-decoupled two-leaf MSM isolation.


- Stuart -

[2k4s]

Thank you Stuart! This makes so much more sense.