Most are 4 1/2 inches thick. 3 1/2 studs with 1/2 inch drywall on each side. There is usually no reason to use wider studs.
any project i do it 2x6 walls all around then 2x4 interior walls. Matt O&P Concrete
i really want to know aswell. mine is 12.9mm.
it is about 6 feet thick-and don't you mean how not who?
The ceiling.