@TeroM have you used 45x70 cc45 with 15mm plyfa and then WAB board?
Is it considered excessive with 45x95 cc30 12mm plyfa and then WAB?
As I wrote above, last time it was without plyfa and then 45*70 with cc 30 and only WAB board.
Now it will be an outer wall with 120*45 with cc 60, vapor barrier and on that an installation wall with 45*45 cc 45 lying with upright cross battens at plyfa joints. RIR is run in this space and then 15 mm plyfa and WAB boards.
For inner walls, I need to fill the cc 60 distance with a couple of studs to get cc 45 or alternatively set the plyfa lying with cross battens in horizontal joints (but the instruction says upright so I need to think a bit more about that ...), all according to Säkervatten document.
45*95 cc 30 + plyfa sounds like a lot and steals quite a bit from the room. 12 mm plyfa is also not right as it isn't enough to screw into and you in that case need cross battens in the walls where you plan to attach things. 15 mm plyfa can be screwed into directly without cross battens.
I partly agree with the 15mm plywood, but the 3mm can hardly make it capable of carrying several tens of kilos more?
I do agree that 45x95 might be a bit over-dimensioned, but that's what the walls are built with today, so it feels wrong to downsize.
I was thinking of Cc30 because it is set with Cc60 today and it needs reinforcement; it's cumbersome to change to 45 in existing walls.
But as you say about the plywood, it might be worth considering. If I set studs on Cc30 45x95, maybe I only need a wab board. And where the vanity is, you can set plywood, and you can also add nogging. It's more about the handicap adaptation that I've been considering, but on the other hand, I can access the toilet from behind, and in the shower, there's a concrete wall...
Will probably go with Norgips Humidboard 2.0 for my part since it works with Kiilto Kerasafe. The WAB board doesn't work as it's non-absorbent, which Kerasafe requires.
I partially agree about the 15mm plywood, but those 3mm can hardly make it support several tens of kilos more?
I agree that 45x95 might be a little over-dimensioned in that regard, but that is what the walls are built with today, so it feels wrong to reduce the size.
I thought of CC30 because it is currently installed with CC60, and it needs to be reinforced, it's cumbersome to change to 45 in existing walls.
But as you say about the plywood, it might be worth considering. If I set studs on CC30 45x95, maybe I only need a Wab board. And where the cabinet is, you can put plywood, and maybe add a noggin as well. It's more about the accessibility adaptations I've been considering, but on the other hand, I can access behind the toilet and in the shower there's a concrete wall..
12 mm plywood = Deviation from the spec = not professionally built. I'll leave the strength calculations to others.
CC 30 or CC 45 doesn't make much difference in the work, just as many studs you need to add in the gaps, but CC 30 probably gives a sturdier wall with the plywood, and 90 boards can still be jointed over studs, it's just 1/4 more screws to drive in ...
Hmm yes in a way deviation, at the same time safe wet room is a recommendation and not a requirement!
The reason for 12mm is because you pay 200kr per sheet for 3 mm later, therefore it felt a bit hard to justify with 15mm.. Will have to think about it as well starting to feel expensive now
Small change
I have used these which are even more expensive but incredibly easy to mount horizontally. I have cc 30 studs 45x70 except on one wall where more depth was needed so there I have 45x95. Big difference if you press a stud inward but when everything is screwed together I don't think it makes a big difference.
Small change
I have used these which are even more expensive but extremely easy to mount horizontally. I have cc 30 studs 45x70 except on one wall where more depth was needed, so there I have 45x95. Big difference if you press on a stud inward, but when everything is screwed together, I don't think it makes much difference.
starting to feel expensive now 
