John Sayers' Recording Studio Design Forum Archive

Hi all

I am currently having a new house built with a detached music room which will/has the frame built, before i finish the internals with a room in a room design.

The builder was/is planning to use rendered EPS (expanded polystyrene) as the external cladding, which is part of the plans we had drawn up by a draftsman & engineer. But i am starting to get cold feet on that idea as all my research suggests it has no soundproofing qualities at all.

The builder has been good allowing me to see if i can find an alternative, but i'm a bit lost with deciphering what would work/be better.

I am in Melbourne Australia

Does anyone have any experience in this area, who could point me in the right direction?
I have tried to search through this forum but i couldn't find anything.

Any help would be greatly appreciated as the build has gone pretty seamlessly so far and i don't want to hold it all up.



Sorry i cant seem to upload image of plans.


Cheers Ben

Hi all, so in the end i went with cinder blocks (hollow cement blocks here in Australia) filled with sand instead of the EPS (foam). Im definitely sure it blocks a lot more sound as we had the rest of the house cladded in EPS (much better energy rating apparently ) and i can hear alot of external noise in the house but not in the studio/music room. Im in Melbourne, Australia

My new question is;

I was planning a room in room design and have started already (its been a very long & slow process as i've been building it in my spare time and its been hard to get timber) and i have one secondary internal wall frame done.

But now im concerned i've created a 3 leaf system as opposed to a 2 leaf system. I have discovered there is a 15mm - 1/2 inch air gap between the cinder blocks (cement blocks) and the 2 layers of plasterboard attached externally to the first wooden frame.

[img]studio%20drawing.png[/img]

Do i continue building a room within a room or use iso clips and 2 more layers of plaster attached to the one wooden frame?

I trusted the builders but couldnt check everything in these COVID lockdown times and now im so lost & worried ive stuffed it all up.

Any help/advice would be appreciated.

Cheers Ben

your drawings didn't come through. that said, if gap between your "exterior" drywall and the block wall - insert semi-rigid fiberglass or even spray-in foam. this will eliminate the air gap if you're concerned about LF 3rd leaf TL reductions. worst case it will damp any resonances there. then build your inner frame and attach drywall to it. no need for clips etc there which can reduce the TL. the only time you would consider the clips and hat channel would be to build on the same frame as the exterior. but since you've already applied the drywall on the exterior frame, it will be much less effective than a separate inner frame.

Thanks Glenn. You have eased my mind. Cheers