Acoustic Plasterboard options

[StepOne]

We have a set of recessed shelves in our living room, directly above a similar set in the neighbour's flat below. We can clearly hear their tv when it is on. It's not too bad if we also have our telly on, but if you have people round and are just chatting then it is noticeable.

The back and sides of the shelves are thin, and sound completely hollow when knocked. To try to reduce the noise seepage, I'm proposing to line the shelving unit with something - the more solid the better. A bit of Googling threw up this;

https://www.insulationsuperstore.co.uk/ ... -24mm.html

Looks like it would do the job, but is bulky and I'm not sure how I would go about cutting it. Also expensive, but less of an issue for a small job. And it doesn't have finished edges so there would be extra work to cover those. Easier to get, cheaper and easier to handle would be this;

http://www.wickes.co.uk/Knauf-Sound-Pan ... m/p/224657

(There's also a 15mm option). What I'm not sure about is whether the second option would be good enough? Does anyone have any experience of using it and whether there would be a noticeable reduction in sound getting through?

In order to line the unit I'll need to cut the board into 12 rectangles, from roughly 30x30 cm up to about 70x70 cm. I was planning on using drywall screws to attach it to the existing wooden walls of the shelves, but I am wondering whether using some kind of adhesive might be a better way, possibly even trying to leave a small gap between the wood and the plasterboard. I feel that an air gap would also help prevent noise transfer. The insulation superstore website recommends using this to seal around the edges of the board;

https://www.insulationsuperstore.co.uk/ ... -tube.html

That product describes itself as a 'sealant and adhesive'. Would something like that be good enough to attach the plasterboard to the walls, bearing in mind each piece of board would be sitting on the shelf below it.

So I'm basically asking if anyone has a view on the best product to use, and also the best way to fix it to the existing walls to reduce noise.

Thanks in advance,
StepOne

[bungeejumper]

So are you saying that the noise leakage occurs only in the area of the shelves? I'd find that a bit improbable, personally, but I expect you've got a better idea of the geography than I have.

There are some excellent below-floor sound insulation products out there, and I don't think they're that expensive. (Although the pain of lifting every fourth floorboard has to be written into the equation.) One of our leaseholders has gone the full hog and is well pleased with the results.

BJ

[StepOne]

Hi,

The sound is definitely loudest when you stand with your head next to the shelves. They are recessed a foot into the walls, so at the very least there is a layer of lath and plaster missing that would otherwise be blocking the sound. Tapping on the back of the shelves sounds completely hollow. I have no idea what would be behind them except fresh air and then the external brickwork (the building is approaching 100 years old).

If lining the shelves makes no difference then we might look at the floor, but that is just such a bigger more expensive job to consider...

StepOne

[bungeejumper]

Aha, that's clear. I wonder whether the reason for the louder sound by the shelves might be that they're collecting the sound and bouncing it out horizontally across the room, like an ear trumpet in reverse? Of course, the fact that your downstairs neighbour has his TV in exactly the same location may mean that you've got your very own speaking tube intercom?

I'd try whacking down whatever soundproofing materials you can find onto the floor of the shelves - piles of towels, old jumpers, anything soft - to see whether it made a difference to the sound reflection. If so, then take it away with a proper go with the acoustic plasterboard.

BJ

[malakoffee]

Hmmm, tricky one.

You speculate that the sound from the neighbour's flat ( below ) is passing through the air cavity, between the inner and outer layers of brickwork.

If so then trying to block noise can only be a matter of experimentation. Increase the blocking mass & ensure no air-leaks.

My immediate thoughts jumped to - I would lose the alcove and restore the inner leaf with brickwork / blockwork.
If blockwork, then choose dense concrete blocks rather than lightweight concrete blocks.

I have an extension on this bungalow with 15mm acoustic plasterboard for the ceiling. Those boards were relatively very heavy compared standard plasterboard sheets. Unfortunately, I cannot give you any information about their sound performance relative to standard boards, because I have nothing to compare them with. Plus that there is about 350mm of rockwool-type insulation laying on top.

Resolving sound transmission problems can be difficult. I hope that you find an easy solution.

[tea42]

A small airgap and an embedded steel sheet or plate would gives the best noise insulation. A triple glazed window insert would be pretty good too and easy to source.

[StepOne]

My immediate thoughts jumped to - I would lose the alcove and restore the inner leaf with brickwork / blockwork.
If blockwork, then choose dense concrete blocks rather than lightweight concrete blocks.

Yes, we've talked about that as well - if all else fails that's what we'll go for. Although the shelves have an attractive edging all the way round, which I would be happy to leave, but which my wife says would have to go if we are blocking off the shelves, which will make it a much bigger job

Resolving sound transmission problems can be difficult. I hope that you find an easy solution.

Thanks, me too. I'm not expecting the outcome to be total silence, but any kind of improvement over what we've got would be great.

StepOn

[Gaggsy]

If you can bear to fight your way through the registration process you can get free access to www.robustdetails.com where you can find a wealth of information about sound proofing. It's primarily aimed at new buildings but you might find some helpful information there.