Sound insulation

The Bear · 21 Jul 2018

Anyone got any knowledge of the best way to reduce sound between my ground and first floor? I see there are a whole host of rockwool type products out there, anyone recommend whats best and how to install. Are they any good? I have access to the voids between the joists at the moment until I re-tac the ceiling. My joists are 200mm deep, do I need to fill the void or just lay out 1 layer of 100mm insulation? What do you do around spotlights and cables in terms of them not dispersing their heat if insulated.
I do understand that this will not completely kill the noise as some will still transfer through the joists. Reason for doing this is that I work shifts including nights and our bedroom is above the main living area so want to reduce the day time noise getting from downstairs to the bedroom above.

Any help greatly appreciated

Mark

sunnybob · 22 Jul 2018

rockwool loft insulation. fill the void but dont pack it too tight or you will lose some efficiency.Use string or webbing to hold it up till the boards are on. Its non flammable.

Woody2Shoes · 22 Jul 2018

A good short-term solution might simply be a couple of extra layers of carpet - upstairs. You could probably get a couple of offcuts very cheaply.

Rockwool (the denser the better) between the joists will definitely help - and you're quite right to be concerned about protecting downlights in the ceiling (even the newest LED ones can generate a significant heating effect) - you can get little fireproof 'hoods' which keep insulation off the top of the luminaire. Once the rockwool is in place, sound can still be transmitted through the joists - if you can re-lay the floor upstairs on top of some sound-insulating medium (e.g. https://www.hushacoustics.co.uk/sound-c ... st-strips/ ) , so much the better.

I'd guess that at the moment, much of the sound is coming via the holes in the plasterboard ceiling where the downlights are (plasterboard is surprisingly OK as sound insulation - mainly because it's quite dense) and another option would be a second layer of acoustic plasterboard on the ceiling and/or finding some way to replace the downlights e.g. with tracklights or something.

Cheers, W2S

paulm · 22 Jul 2018

Just to mention that rockwool type products will give some benefit, but there are specific types also that are used for acoustic insulation rather than just heat insulation (although that is a benefit also).

Can't recall the details but I used some acoustic stuff in my recent workshop refurb', may have been RWL34 or similar or I might have got that completely wrong !

It did make a dramatic difference to noise and warmth from a 70mm thickness, very impressive.

Woody2Shoes · 22 Jul 2018

e.g. http://www.rockwool.co.uk/advice/acoust ... nd-floors/

Eric The Viking · 22 Jul 2018

What age/type of property is this?

Chimneys in both rooms sharing a common stack can be a nuisance, as often there are holes between the flues and these are impossible to block and transmit noise very well. If you have that sort of thing, it merits further discussion. Otherwise, see below.

The most cost-effective and easiest thing to do initially is to put 6mm ply (fairly reasonably quality) down in the bedroom, then a _good_ underlay and a good carpet. To be pedantic, ensure you seal as many air gaps around the edge of the room as possible (boards or chipboard to wall or under the skirting).

You won't get much structural noise going upwards - it's mostly airborne. careful attention to detail sealing the possible routes makes a huge difference, as will the carpet.

Rockwool : mostly pointless in this context. That means not always - sometimes very helpful, but not really in this case, as the ceiling plasterwork will kill 95% of the sound. As you thought, it might also cause problems with the light fittings warming up, and if you put big loads on the upstairs ring mains in the winter.

E. (background in audio with some experience of studio acoustics).

thetyreman · 22 Jul 2018

hardboard works well as well because of its density vs thickness, I used hardboard in my studio under the carpet underlay which helped to make the room as airtight as possible before sealing it with silicone. Sealing any air gaps and making it as airtight as possible is critical if you are serious, even a tiny gap will leak a huge amount of energy.