soundproofing party walls

[pedmon]

I was having a lot of trouble with noise from neighbours. Their stairs are adjacent to our living room and bedroom. I could hear them running up and down the stairs, talking, shouting etc... all very annoying!!!

So I have put up 2 massive stud walls (up stairs and downstairs against all party walls). I have used many 3x2 uprights and verticals. dense rockwool insulation and 1/2 inch plasterboard (standard stud walls).

51 x 3x2 2.4m lengths (includes all verticals/horizontals and noggins)
12 x 1.2x2.4m 1/2 inch plasterboard
50 x (50mm) dense rockwool slabs

I have reduced the audible noise by a lot. However I seem to have increased the impact noise dramatically. I now hear the neighbours walking around in their house next door. The sound now ripples through into our ceiling across to the otherside of our house (it never used to!!!!). The timber frame is screwed into the outside side walls, concrete floor (downstairs) and into joints (upstairs floor/ceiling). I think the main problem is that the impact noise is resinating the wooden frame which in turn is transferred up into the ceiling joists and across the house.

My dilema now is that I really want to remove the stud walls (big mistake i think in the first place,quite a job really to put up and take down) and replace it all with foam backed plasterboard instead (either glued or hammerfixed into party wall) . Hopefully will give a slight reduction on impact and audible noise. Hopefully this will reduce any resinating sound from the existing wooden frame (which will be removed). And I should gain a couple more inches of house back.

It doesnt help that the houses are staggered, which means part of next doors upstairs is adjacent to our downstairs. (these are 1960s ex-council houses by the way). I believe the party walls are just single breeze with no insulation between. Hence the noise.

Any experience or help appriciated before I rip down a lot or wood and plasterboard.

 

[JohnD]

The timber frame is screwed into the outside side walls, concrete floor (downstairs) and into joints (upstairs floor/ceiling).

unfasten it from the floor joists before you do anything else. You can pack the gap with your fibre.

Have you lined under the stairs; and have you got stair carpet? have they?

 

[JohnD]

My apologies, I was talking rubbish again. I have just remembered that to reduce flanking sound from next door, the barrier is supposed to be fixed to the floor and ceiling, not the party wall.

Best to ignore me

here is some stuff on http://www.customaudiodesigns.co.uk/articles/howtowalls.htm

 

[Bambi]

Natural sound travels in 2 ways, through the air/atmosphere and through solids.

Therefor, you have 2 areas to address.

The first is the noise from the stairs, walking around and any banging. These are all mainly transferred via solids such as the joists, walls, floorboards etc.
There is very little that can be done about this because the structure of the building will not permit isolation from your neighbours as far as solid transmitted sound is concerned. The only coarse of action is for your neighbours to fit accoustic underlay under their carpet and on each tread of their stairs.

The area where you are in control however is sound that is transmitted via the atmosphere. The wall you installed reduced the sound from the atmosphere and increased that from solids because by installing the wall you increased the solids that sound could travel from and, in effect, created a drum. Your wall being the skin of the drum.
The new wall should not come into direct contact with ANY solid matter (joists, concrete floor, walls etc.). I know it sounds impossible but it isn't, I've done it in my purpose built cinema.

You need to fit a butal based membrane between the studwork and solids. A bit like damproofing between brick and base. The membrane needs to be at least quarter of an inch thick. the method of fixing needs care too. It is not advisable to use ordinary Fisher type bolts, screws and/or nails. If you use screws, you must use rubber washers and the whole must be lined with a rubber grommet.
The idea is that the wall is actually cushioned from all contact with ANY solid. Obviously fixing the noggins and internal uprights can be fixed in the normal way.

Once the wall is constructed, it needs to be filled with a dense Rockwall or other brand of insulation. I used RW6 which is very, very dense. If you install mains sockets in the wall, fix them with silicone mastic to prevent any vibration or noise transference.

Once all the insulation is installed, run a line of silicon mastic between the crack of insulation and timber.

Now fit sheets of accoustic plasterboard. Again run silicone along all joints.

On top of this fit fireproof plasterboard (pink).run a line of silicone mastic around the edge of each board between the accoustic board and fireproof board.

Plaster and decorate.

If this don't work, either threaten your neighbours with violence or consider moving.

Good luck,

Den

 

[pedmon]

Thanks Den,

Sounds great. However money and sanity are very low at the moment. So limited to what I can do.

I intend to start taking down the 24/26 foot wall (gulp!) down stairs this weekend. That will give me a chance to see how much difference it will make. The upstairs I have skimmed so thats a bit wasted. However I can utilise the stuff from downstairs for my false sloping ceiling and hallway ceiling that needs reboarding.

Obviously I would move (not going to happen for a few years really, finances being as they are, have to make do for a while im stuck here for a few years)

I will have to try a cheap combination. Maybe soundproof foam backed plaster baord straight onto the party wall fixed in with rubber grommits and rubber washers. no touching floors outer walls or ceiling. Then line the outer gaps with silicone or equivalent. Then skim before decor.

I cannot really reuse the timber frame for same purpose again (its well and truly fastend to the floor, ceiling and outer walls. Needs damaging quite a bit before it will come out).

 

[hairyjon]

Hi Pedmon You say your house was built in the sixties? Is it a prc home(pre-cast reinforced concrete) that was so popular between the end of the 2nd. world war and the mid-60's?

 

[pedmon]

Is it a prc home(pre-cast reinforced concrete)

Not sure, dont think so. Its a concrete ground floor with underfloor elec heating. construction is standard bricks and tiled roof. Houses are just staggered. So one neighbour is above and one neighbour below (slightly). And all face the same way our living room to neighbours stairs, not stairs to stairs (when it comes to ajoining party wall).

 

[hairyjon]

Ok Pedmon. Just a thought. I have an Airey prc home and have had alot of problems with noise due to the fact that there is an open cavity between ground floor ceiling and upstairs flooring that is only seperated by a single layer of concrete blocks between houses for fire protection. Joists are steel and the sound carries from one end to the other!

 

[pedmon]

Mainly a lot of noise due to

1) noisy neighbours (heavy footed kids and very irritating dog (that needs its bark removing )
2) possibly only single breeze party walls
3) no sound insulation between them ( they didnt really bother in the 60s apparently, not with ex council)