Minimum dimension for joists for soundproofing.

[zeltber]

We have just added an upper floor to our villa. We have built a 195 bjkl 30cc and would like to achieve really good sound insulation in two of the rooms (bedroom on the entrance floor and family room on the new upper floor).

I'm considering decoupling an additional beam layer under the new one, thinking I can place ground board in the stronger upper part and something like foam in the lower part (to achieve different properties). Any thoughts and ideas?

The span is 450 cm at most. Will I manage with 95 studs 60 cc in the floor structure (bearing only gypsum and foam or similar)?

 

[ZipLock]

Can recommend using steel rules and sound brackets instead. Easy to install and greatly improved sound level when it comes to footstep noise.

http://byggsystem.knaufdanogips.se/mounting/m_floor_decks/

 

[vectrex]

We have just added an upper floor to our villa. We have built a 195 bjkl 30cc and would like to get really good sound insulation in two of the rooms (bedroom on the entrance floor and living room on the new upper floor).

I am considering decoupling an extra floor structure under the new one, thinking I can put a ground board in the stronger upper one and something like cellplast in the lower one. (to get different properties) Any thoughts and ideas?

The span is 450 cm at most. Can I manage with 95 joist 60 cc in the floor structure (bearing only plasterboard and cellplast or equivalent?)

450 cm span? That will likely become a good drum. I don't think 95 joist is sufficient if you want to have a smooth plaster ceiling; it will crack.

If it's impact sound you want to get rid of, your solution is probably the best, but it does require a lot of space. For all other sounds, two other things are most important. Airtightness and heavy materials (floor plaster or self-leveling compound), seal all joints so that it becomes completely airtight.

 

[zeltber]

95 is
Probably too little. In my case, I have no way to influence the floor upstairs but all furniture

 

[zeltber]

Possibility to lower the ceiling on the entrance floor. Preferably 25cm. Most systems seem to be designed for apartments where you want to retain as much ceiling height as possible.