I'm considering if it's enough with boards only on the bathroom side (15 mm plywood + drywall on a 70-stud) when trying to separate sound against, for example, a bedroom. The idea when designing the "bathroom wall" from "Säker Vatten" must be that it includes reinforcing boards on the other side of the studs. Is there perhaps a way to connect the studs without transmitting sound? Attached is a picture of what I mean, which is stolen from this thread: https://www.byggahus.se/forum/threads/brandklassad-avskiljande-vaegg.326308/
if it's enough with boards only on the bathroom side
What are you going to have on the bedroom side?
When building a sound-insulating wall, you usually offset the studs on the different sides relative to each other, have a larger air gap, and ideally use rock wool, which has a higher density.
Following the attached image, you will get excellent insulation between bathroom and bedroom while the wall meets secure water requirements. However, it is quite an expensive wall to build. I believe it's sufficient to fully insulate and bond a 70mm frame with gypsum+plywood on one side and gypsum x2 on the other. Additionally, the described wall also takes up a lot of space.
When building a soundproof wall, you usually stagger the studs on the different sides relative to each other, have a larger air gap, and preferably use rock wool which has a higher volume weight.
On the actual bedroom side, it will be OSB and gypsum.
I meant that on the stud facing the bathroom, there will be no sheet on the other side.
But then I realized after the post was written that you could make the bathroom framing sturdier by placing an OSB on it while the bedroom wall is still open. However, it will then be an additional 1 cm thick. And that might reduce the effect of a soundproofing wall with a sheet there.
@sixten88, yes, a bit overworked but there will be a washbasin and shower and therefore waste/water pipes in that wall, so the question is whether it will be quiet enough. With an empty wall, I wouldn't have thought about it.
Indeed, I think the "simpler" 70-rule is enough, meaning boards only on one side.
But if you are worried, you could overlap them and use a larger rule on the bathroom side, for example, 120mm?
