How thick must be the concrete wall?

I start to build a studio and It gona be a bunker , 15 cm outside wall 12cm inside wall, floating concrete flor and cealing, Do I need more for isolation?, to don't worry about anoing my neigh'?any one have any experience whith this type of construccion?

Bojan wrote:

I start to build a studio and It gona be a bunker , 15 cm outside wall 12cm inside wall, floating concrete flor and cealing, Do I need more for isolation?, to don't worry about anoing my neigh'?any one have any experience whith this type of construccion?

There are too many local issues (soil bearing capacity - clay content in soils - water levels - etc., etc., etc.) to be able to even begin to consider an answer to a question like that at a distance - and if anyone did answer it they would be lying out of their teeth.. You need to hire a local engineer (structural) to design a structure like this. Bring an acoustician on to design the floating part of the room and to assess your isolation questions. Rod