How to improve soundproofing of a wall?

[Mark21]

I have a wall between a bathroom and bedroom which lets through a lot of noise through.  Noise is both airborne and shower head/water pipe vibrations. Below is a picture, before it was finished a few years ago.  Bedroom side was finished with Fyrcheck.  Not going to touch the bathroom side, which is tiles.  Can I do much to improve sound insulation?  If I cut away some of the plasterboard and compress another layer of Earthwool in, would that help?  Anything else I should think about? 

[CSParnell]

Hi @Mark21 welcome to Workshop, with sound and insulation it cones down to density of the product rather than how thick the product is measured in kg/m3.

Sound travels in waves and there needs to be enough dense fibres tightly packed in to dampen those waves.

Yes fibreglass bats and earthwool will help some but recording studios will use products like Rockwool that are designed for this exact application along with dual layer 16mm plaster board. 

This handy little book I shared with @EricL The other week explains some good processes of soundproofing it my be of some help.

 

[EricL]

Hello @Mark21

Allow me to welcome you as well to the Bunnings Workshop community. It's a pleasure to have you join us, and thank you for sharing your question about soundproofing.

The insulation suppliers called it a point of diminishing returns. Your wall can only take so much insulation that it no longer provides adequate insulation. All sorts of things start to go wrong from moisture contamination to fluctuating temperatures inside the house. 

Because the wall has already been plastered and painted, instead of cutting into the wall, I suggest putting on a timber batten frame in front of your existing wall. I propose putting in Pink Soundbreak 1160 x 430 x 90mm R2.7 Batts - 8 Pack in combination with Gyprock Soundcheck ( special order product ). These two materials will provide superior sound insulation for your bedroom. 

In essence, you'll be putting a wall in front of your wall, this extra wall will be taking an approximate space of 120mm++ including the skirting board. I understand that it sounds a bit overkill, but when you add up the amount of quiet sleep you'll be getting, building that extra wall sounds like a bargain. 

If you need further assistance, please let us know.

Eric

[Mark21]

Thanks.  Yes, that would definitely be the best solution, but unfortunately cant lose that must space in the room.  And the door reveals would look huge!

[Mark21]

Thanks.  Bought the book and had a read. 

[EricL]

Hi @Mark21

I hope the book has given you ideas, I've drawn up a basic sketch of what your wall might look like if you should revisit the added wall recommendation.

Eric

[CSParnell]

How did you find the book @Mark21 ?

[Mark21]

I wish I had read the book while the builders were building the wall.  A lot of the recommendations are difficult unless I go for a full double wall.  So its a matter of trying to apply some of the ideas on just the one side I can get access to. I also bit the bullet and asked an acoustic guy to come  in and give advice.  I'll let you know if his ideas are different.   

[CSParnell]

Sometimes you make do the best you can with what you have and you have to make peace with that.

[MitchellMc]

Speaking of making the best with what you have, @Mark21, did you know hanging thick woollen rugs from your walls retains heat and is an effective sound barrier? This trick has been used for generations on dwellings with thin walls and limited heating options.

Please keep us updated, and reach out if you need further assistance.

Mitchell