Advice reqd on soundproofing please


Active Member
I'm well underway building my new cinema room and would like some advice on accoustic insulation for my ceiling.
There is going to be a bedroom above and I would like to keep sound from bleeding through.
I also want to make the cinema sound as tight as possible by minimising vibration in the airspace between the joists.
The ceiling is of standard construction consisiting of 200x75mm at 400 centres timber joists and plasterboard ceiling.
Any help appreciated regarding insulating materials and recomended sources.

Peter Parker

Distinguished Member
With walls you usualy fill the gaps between the beams with 4" rockwool, then fit two layers of plasterboard - staggering the joins so they don't line up.

You could try a similar thing with the ceiling.

Also ensure all air gaps are filled with silicon or similar, such as the gaps between the floorboards and the skirting and floorboards in the room above. Where air can go, so can sound.

Wickes do everything you need, including a 30mm high density slab. It'll probably be easier to remove all the floorboards from the room above, and cut the slabs to fit between the joists.

Fit the 30mm slabs as the first layer (make sure they're a snug fit), then use the 65mm slabs to finish. Refit the floorboards and fill all gaps. Fill the gaps between the boards and skirting. Use Wickes high quality rubber underlay under the carpet before refitting.

Then add the second layer of plasterboard to the ceiling of the cinema room. This'll add rigidity to the ceiling joists, and help with bass sound transmission. Fill the edges with sealer too.

There's not much you can do about bass vibration unless you build a complete room within the existing room to totaly isolate any vibrations from the adjoining room, but this should be a start at least.




Active Member
Thanks Gary
I actually found a thread on the subject from a while back and have used the 30mm HD slabs from Wickes (still itchy!!).
Give me another couple of months and I should be able to publish pics of the finished room.


Peter Parker

Distinguished Member
Great - I'm looking forward to the pics!

Any way to tell how effective it'll have been? A before and after is always handy for future reference.


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