Building A Stud Wall With Metal Studding

[j0nb0y]

I am thinking of taking a stud wall down in my bathroom and replacing it with a metal stud wall, I am doing this to extend the bathroom 6 inches into a bedroom to make room for a shower bath.
I have not used metal stud walling before and have a couple of questions:
1) what thickness plasterboard do I need to use with metal stud walling, bearing in mind it is going to be tiled on one side.
2) what centres would I need to set the metal studs at?
I am thinking 12.5mm Moisture resistant Plaster board on the bathroom side and 12.5mm normal plasterboard on the bedroom side, with studs at 400mm centres. With accoustic insulation in between the studs. Not sure if I am supposed to use 15mm plasterboard with metal studding?
Any advice, greatly appreciated.

[Zacs-Master]

Normal 12mm plasterboard (I would recommend using one with acoustic reducing properties for the bedroom side to cut down ‘noise’ from the bathroom). Studs at 450mm / 500 centres for uprights and 1.0m vertically. Think about plywood for the inner face. Water gets everywhere, eventually.

[The Builder]

Zacs is on the case, but I have a couple of things to add.

Definitely use "moisture- resistant" on the bathroom side.
12.5mm thickness (I don't think I've ever come across 15mm plasterboard.)
12.5mm "Soundcheck" or similar for the other side.
Sound-reducing boards are very heavy. If you've got to lug it all upstairs, then 12.5mm ordinary plasterboard......
Or.......... even better, two layers (25mm). Sound reduction relies greatly on "Mass". The thicker, the better.

I would have to say 400mm centres, or the board won't line up for fixing (boards are 1200mm x 2400mm)

Do satisfy yourself that the stud wall you're taking down is non-loadbearing. It rather depends on the age of the house.

[j0nb0y]

I have used 15mm p.board before, very heavy stuff. Its not a load bearing wall. It is a stud wall construction I have never come across before. It is two plasterboards with straw sandwiches between it, no timber studs.

[The Builder]

You're right, jonboy. "Knauf" make a 15mm plasterboard.

"Straw panels" have been around for a long time, but I can't say I've ever come across them. Maybe it depends on which part of the country you're in.

[j0nb0y]

I only knew my walls were of that construction when I was making a single socket into a double in the bedroom. Looked like I had been keeping chickens in there by the time I had finished. They are only 50mm thick as well. That is one of the ressons I am using 50mm metal stud, will be 75mm with p.board. But if I used 3 x 2, then p.board, it would double the thickness of the existing walls.

[j0nb0y]

Thanks both of you for the replies.

[Ryzen]

jon...to add to TB and ZM....if the shower/bath is on the new wall consider using Hardy backer wall boards or equiv...these are cement based...so, if and when any water gets through the tiling it wont destroy the board....green boards are only moisture resistant..not water proof. Also confirm that any wiring circuits passing through the metal stud are RCD protected.