11mm OSB then PB on ceiling?

[Carrerahill]

As part of my ongoing works I have started to sort out some of the original house rooms that tie into the extension, I have a small room, 6m sq. which I tore down the old ceiling for many practical reasons and just to renew it as it was a bit cracked. 

 

Above this room is a bathroom, the room will be repurposed as a little office/den. I have been thinking about lining the ceiling in 11mm OSB, then 12.5mm PB. I did think about twin PB sheeting the ceiling, but I have something in my mind about the OSB being a good idea. 

 

There are some thoughts to my OSB lining plan, it will create a good solid ceiling and help to stop some noise, I have about 15 sheets left over from the build, it will mean when the bathroom is being done up and the floor is up there is a slightly more solid covering so when things are being bashed about it is less likely to damage the PB etc.

 

Has anyone done this? I know lining walls first is commonly done but ceilings? 

 

Does anyone think the 11mm OSB would sag overtime, the joists are on 20" centres - I had thought about cutting a load of 4x2 blocks and adding some additional support that I can fix to.

 

Basically the theory is a rock solid ceiling with slightly better acoustic properties than a single sheet of PB.

 

I would appreciate thoughts here, I am sure someone may suggest going for soundbloc or something but ideally I would like to use materials I have here as waiting for delivery (about 3 weeks from my friendly merchant just now) is just not happening.

 

 

 

 

 

 

 

 

[the_r_sole]

I can't see it giving you any acoustic advantage as the noise is transfered through the structure, if anything it might transfer more noise? Plasterboard is much better for acoustics, two sheets would definitely outperform osb and 1 sheet, resilient bars would be the rolls Royce ceiling here

[Carrerahill]

3 minutes ago, the_r_sole said:

I can't see it giving you any acoustic advantage as the noise is transferred through the structure, if anything it might transfer more noise? Plasterboard is much better for acoustics, two sheets would definitely outperform osb and 1 sheet, resilient bars would be the rolls Royce ceiling here

 

I think you are quite right...

 

Resilient bars... I know what these are and how they work but have no knowledge of "systems" or who/where etc.

 

A quick google suggests I could basically buy some, fix them across the old ceiling and board away. Hmm.

 

 

[the_r_sole]

Have specified knauf ones before (but no idea if they are the best, just had decent technical info!)

Pretty sure you can get British gypsum ones too...

[Carrerahill]

https://www.soundinsulationstore.co.uk/products/standard-resilient-bar?gclid=Cj0KCQjw9b_4BRCMARIsADMUIyo5H5MmUS1DtJMhk_iR3e6j_G5tnD8wji-IHWKL6IADy9aiw9k7peAaAgovEALw_wcB

[nod]

No advantage to fixing timber for acoustics 

Res bar would be a cheaper and quicker option 

With a layer of 15 mil SB 

[Carrerahill]

I'll have a look.

 

 

[Nickfromwales]

+1 on the OSB doing nothing. It may even  make things worse.

[joe90]

The only thing I would change with my new build is to use resilient bars and/or double boarding. Despite ceiling insulation to latest spec and single 12.5 PB sound can be heard between floors ?