Poor Party Wall Sound Isolation

DaveyDave · 19-09-2020 12:51pm

Just getting this rolling again, still waiting for the developer to get back to me. Who/what am I searching for to get tests gone? The blowers tests, is it possible for the wall to be plastered well but the party wall block is poorly constructed, would the plaster hide the issue?

I was reading a presentation that said a 6mm hole in the construction could increase sound by 10dB. We're hearing absolutely ****ing everything. In the spare room we hear the kid next door talking to himself while playing in his room. This is absolutely not adequate sound dampening.

I am concerned the neighbors won't allow anyone enter the property to test the walls (they're knackers and the guy smokes weed all day and likely wouldn't want someone coming in unannounced).

Ideally what I'd like to do it have the party wall checked and if it's not done properly have the developer put a fix in place. There's no way I'm hearing voices in the other room while other houses don't have this issue and this is adequate.

Dont Be at It · 13-10-2020 4:58pm

wersal gummage wrote: »

Presume to do this properly you'd be lifting skirting and removing coving yeah?

We did internal insulation recently and the coving all had to be handmade to put back, cost a fortune. If party wall is the dab method, would it be a complete gunter job to just cut the plaster away below the coving line, put some kind of slim sound board in and plaster? Would that even be possible anyway or would the wall then extend out beyond the coving line.... And presumably all of the noise would just come through the weak point??

Hmmm.

I'm in a similar position - I was going to bring the sound board to within ~300mm of the coving and then place my picture rail decor at this level as well. So the top of the picture rail and the top of the sound board would be at the same height and the picture rail would hide the edge of the board.

To the wider thread - is my approach of 25mm insulation overlaid with 12.5mm sound proof plasterboard (skimmed), all pinned to the wall with mushroom fixings a good approach to attain a reasonable degree of sound proofing?

Yellow_Fern · 13-10-2020 5:37pm

Dont Be at It wrote: »

I'm in a similar position - I was going to bring the sound board to within ~300mm of the coving and then place my picture rail decor at this level as well. So the top of the picture rail and the top of the sound board would be at the same height and the picture rail would hide the edge of the board.

To the wider thread - is my approach of 25mm insulation overlaid with 12.5mm sound proof plasterboard (skimmed), all pinned to the wall with mushroom fixings a good approach to attain a reasonable degree of sound proofing?

I am in a similar boat so I am no expert, but if you want to have a chance of removing those distant impact sounds, I think it is important that everything is decoupled. Like even the ende of the board from the floor and ceiling. The thickness of the extra plasterboard is pretty insignificant if the wall is already a solid wall.

bleaks · 17-04-2022 1:56am

Anyone have any success here?! In a similar position with poor sound insulation through the party wall. Thought with the house being 70 years old ex corpo (end of terrace) the party wall would be rock solid, but no. It's also a cold house so thermal/sound insulation would be no harm.

C. Eastwood · 17-04-2022 11:44am

https://www.boards.ie/discussion/comment/118937578#Comment_118937578

blesks.

Sound Insulation and Thermal Insulation are two totally different areas of study.

For instance the most optimal cavity in double glazing for to reduce heat loss is 20 mm.

The minimum sealed cavity in double glazing to reduce the transfer of sound is 150 mm to have some effective sound reduction.

Contrary to popular belief that double glazed windows reduce sound- it’s the rubber seals between the frame and opening sashs that provides the reduction of the incoming noise.

Example 1 - If you have a 100 m2 wall with 99 m2 of thermal insulation to reduce heat loss - you will have approx 99 % heat loss efficiency.

Example 2- If you have a 100 m2 wall with 99 m2 of sound insulation- you would have very little sound reduction efficiency.

You stated that your house is an end-of terrace house, and that it is a 70 year old ex Corporation house.

Firstly let me say that 70 year old ex Corporation houses were very well constructed houses. They were constructed when the Craftspersons had to be qualified and were only allowed to work on their own trade.

There was also a Clerk of Works on site making sure that everything was constructed in accordance with the Drawings and Specifications.

Presently I’m looking after the renovations of a 70 year old ex Corpo house.

Timber was expensive in those days and the First Floor Joists are built-in to both Party Walls. This was the shortest span for the first floor joists (FFJ) . Today we would use metal Joist Hangers - which had not invented at that time.

In the photos below, the Party Wall is the one with the Clock and yellow paint. And as you can see the FFJ are built in to the Party Wall. One of the photos is a close up of the joists in the party wall. When I visit the site in the next few days I will send a better photo.

The new grey colour steel beam is supporting the joists, which were supported on a 100 mm concrete block partition which we have removed.

59CF9522-D332-4471-842B-821E4CE44D60.jpeg

0A3B78E5-FDEB-480E-AC85-FE157DBE33B5.jpeg

In between the FFJ are concrete blocks, but the small gaps on either side of the joists are open - sound will go through at these gaps and there are 2 gaps every 400 mm

The home owner and next door neighbour have no problems with noise, so we will only tightly fill and pack these gaps with non-shrink mortar.

This will reduce any Airborne sound/noise.

If there is a noise problem of Doors banging and footsteps on the floors, which is Impact Noise and which would cause Structure borne noise being carried through the joists from one house to the other, it would be necessary to remove the built-in joists from this side of the wall.

I assume (which is a dangerous thing to do in old buildings) that the joists of each house are built in and bearing 100 mm on the 225 mm party wall, with a gap of 25 mm between the joists.

All of this works should only be carried out by experienced qualified Carpenter & Joiner - to do the following:-
provide support to a joist
cut off the end of each joist 12 mm away from the party wall
(only 1 joist at a time)
Fill and pack the hole in the party wall with mortar.
Fix a heavy duty metal joist hanger on to the end of the joist
Bolt the Joist Hanger to the wall
This will reduce the Air borne noise
It will also reduce the Structure borne noise between both houses.

Ensure that all of the gaps in the Party Wall in the Attic are filled with concrete blocks and mortar.

C. Eastwood · 17-04-2022 4:01pm

bleaks

If the tongue & grooved flooring boards are running from the front wall to the back wall of your home, then the First Floor Joists must be transverse to the flooring boards - and will be bearing on the Party wall, an internal partition and on the gable wall.

bleaks · 21-04-2022 11:53am

Really appreciate all the useful info here Mr Eastwood.

I will be taking up the floor in the attic for woodworm treatment and to put in 3/400mm insulation in the next few weeks.

Should I be able to see/confirm if the joists are shared between the houses once I take up the attic flooring?

Not sure if you're Dublin based but no doubt you know the D12 corpo houses in blocks of 4 with two end of terrace facing outward at a right angle at each side. It probably does indeed make sense that the joists were shared across the block of 4 houses.

muffler · 21-04-2022 12:55pm

https://www.boards.ie/discussion/comment/118955734#Comment_118955734

I've never came across joists spanning 2 houses. I'm not saying that it isn't the case in your situation but very unlikely.

DaveyDave · 21-04-2022 1:35pm

Since starting this thread I had an air tightness test done and the result was in spec. I did some work around the window seals with the help of a thermal camera but ultimately they're crap windows from Munster Joinery, the ones in the bedroom will definitely need to be replaced or have secondary glazing put it.

Surprisingly after months of silence the developer got back to me about doing a sound test. When I spoke to the neighbors and they were on board until a few weeks later when I went to pick a day that suits they suddenly changed their mind and were very hostile. The developer asked me to speak with them because the council didn't respond.

Frustrating end to a complicated problem. We know there's issues and we were on track to having it resolved.

I've lived in many houses over the years, some cold or damp or both but never had noise issues like this.

hesker · 21-04-2022 4:02pm

In an estate I lived in once a group of residents threatened to bring the developer to court unless he addressed sound insulation issues. The developer fitted sound insulation on the shared wall. No idea how it worked out. Don’t think it went as far as court.

C. Eastwood · 21-04-2022 9:13pm

https://www.boards.ie/discussion/comment/118955734#Comment_118955734

bleaks

I would be thinking like muffler. I have never come across upper floor joists passing through the Party Wall.

Pack Cement Mortar around the joists in the Party Wall

See Photos of joists in party wall with open joints at both sides of the joists:-

EBB2BDB0-292C-4C56-B46C-834363850C8A.jpeg

2C94C6F4-289F-4919-8610-D3F7F4844FC5.jpeg

B2AEAC0D-7E03-424F-82B8-A713C22677A1.jpeg

E97370C2-3F72-49D5-87F1-D8EA659C2E5F.jpeg

No matter how good the sound proofing of and structure is- any hole in the structure - sound will pour through the gap.

Pack the mortar in at least 100 mm all around each floor joist.

After you treat for the timber for woodworm (Anobium punctatum) Common Furniture Beetle, there will be some parts of the affected timber unreachable. I therefore recommend placing many Woodworm (Anobium punctatum) Traps around the attic or between floor joists. These traps will trap the male beetles.

Yellow_Fern · 25-04-2022 4:54am

@C Eastwood

Thanks for the great pictures. Does the fact that the hole is being sealed only on your side have a negative impact? Is cement the only material? Are acoustic sealants suitable for this job? Is there any gain to be had from painting the blocks to further seal? Would you put some felt or foam around those pipes while its open to prevent creaking?

C. Eastwood · 25-04-2022 1:46pm

Hi Yellow_fern

Thank you for your kind comment.

If you have a wall and there is a small hole in the wall, sound will go through the hole. Block the hole and it will reduce the noise

We are only talking about domestic sounds in a domestic dwelling.

From a practical point of view you can only seal the hole at your side. And that’s fine.

It’s a Party Wall and must prevent the transfer of fire between both houses for 1 hour.

Therefore you could pack /fill the gaps around the joists with Non-shrink Mortar (available in Builders Providers) or fire-proof silicone mastic. It would be easier to pump in the mastic in to the gaps and it would give a better seal

You do not need intumescent mastic.

Acoustic material is fine once it is non-combustible.

Mastic will give a better seal.

The blocks are perfect. Do not paint - waste of time and money.

If pipes are causing a creaking noise, I assume they are Copper or some other metal, it’s OK to put /pump mastic in to the holes in the joists around the pipes.

If the pipes are plastic. Do not put Mastic or any other chemicals near the pipes as they may change the structure of the plastic pipe and cause leaks 💦 . Put up with the dry creaking 😂😂.

bemak · 04-07-2022 11:48am

we had this problem in our house when we bought it. (70s construction). the joists are probably embedded in the party wall looking at the front elevation (shortest span) and that definitely doesn't help, particularly as the neighbours joists are likely to be using the same centres. I saw this in our house - the joists were nearly touching in some locations. In the end I decided against cutting them (as we have a suspended ground floor as well). What we did do was put up a new stud wall along the party wall (25mm gap between the new wall and existing). Used acustuds infilled with isover acoustic roll, a spec I would have used on hotel projects. Then two layers of soundbloc plasterboard to close out. I also filled the first metre or so of the ceiling along the party wall with isover acoustic roll as well to stop reverb. Overall buildup of approx 125mm including the 25mm gap to existing wall. Made a huge difference. We still hear the odd sound from time to time but there's no comparison.

If I was you, I would do a bit of investigation in one of the rooms adjoining the neighbouring property - even a utility or downstairs WC would be ideal as it would limit the remedial work. If you could open up around the ceiling - see what the buildup is like to party wall and if the joists have a large amount of space around them etc.

Plasterboard is relatively cheap - so I wouldn't worry too much about taking it down and redoing it if it meant solving your problem. You could try one room first and limit the cost.

Yellow_Fern · 05-07-2022 3:20am

https://www.boards.ie/discussion/comment/119288214#Comment_119288214

Great advice. Do you feel you killed flanking sound? What was the level of noise before? Could you hear talking before? Do you still hear doors closing?

bemak · 05-07-2022 8:37am

https://www.boards.ie/discussion/comment/119291560#Comment_119291560

We could hear talking much clearer. One thing that sticks with me is that I heard a spoon drop on the floor. None of that since. You'd heard a shout from kids or something the odd time or the creaking of footsteps (because of the joist situation) but it's far better than it was. We're glad we did it that's for sure

nathan184 · 13-07-2022 10:59am

I want to add soundproofing to a party wall and I'm trying to choose between Mustwall 33B and a resilient channel type system like the Reductoclip with two layers of plasterboard. Does anyone have an opinion on which is better?

The house is a new A-rated semi-d. Our wall is a 215mm block on the flat with 15mm sand/cement render. Our neighbors are generally very quiet people luckily, but we can hear raised voices and doors closing clearly and whenever they tap the wall with something or switch on their socket it's loud enough to wake me up. Is that normal or is something gone wrong here?

If anyone knows a good soundproofing contractor in Cork DM me. Otherwise I'll DIY it.

yer man! · 23-12-2022 2:51pm

Just seeing this thread now. Moved into a new build terraced house there a few months ago and can hear the neighbours on both sides. The sound insultation between the houses is diabolical. I can hear normal conversation, if I place my ear to the wall I can make out the words of the conversation. Planning on getting a sound test conducted myself to see if this house was actually properly built as I don't think I should be able to be hearing this crap. Builder has no interest in entertaining any problems I raise with the house. Wondering if fitting my own sound insulation will actually help.

C. Eastwood · 23-12-2022 6:54pm

How old is the house

yer man! · 24-12-2022 12:34am

https://www.boards.ie/discussion/comment/120029615#Comment_120029615

6 months

TimHorton · 24-12-2022 9:05am

https://www.youtube.com/watch?v=ErGqRzzz_Vw , Have a look at what is possible. This guy is a handyman renovating his own house, Also links a UK company who supplied (Sponsored!) all materials.

I feel your pain I left my Semi D New Build 18 yrs ago due to sound issues , We Now live in a Detached House on half an acre , Bliss.

C. Eastwood · 24-12-2022 12:11pm

please let me know if you are a tenant or the house owner.

yer man! · 24-12-2022 3:30pm

https://www.boards.ie/discussion/comment/120031078#Comment_120031078

I own the house yeah, so I can make modifications to reduce the noise level but it's just like another thing to do now.

yer man! · 24-12-2022 3:35pm

https://www.boards.ie/discussion/comment/120030736#Comment_120030736

That does look like the proper job alright. Absolutely not looking forward to the possibility of ripping apart all the walls in the house. I'm not sure my family will cope with the stress :-P Almost thinking it would be easier to move.

C. Eastwood · 24-12-2022 3:37pm

https://www.boards.ie/discussion/comment/120031524#Comment_120031524

Thank You.

Do not alter the Party Wall

I will reply to in the next few days and inform you what to do.

Merry Christmas.

Yellow_Fern · 24-12-2022 7:03pm

If the house was built six months ago, it must meet minimum sound standards which it sounds are not being met. However it is very difficult to use the law to address violations of standards. it would be great to know more about the house, but I am guess it is a timber frame house where short cuts were taken during construction.

wersal gummage · 31-12-2022 1:09pm

https://www.boards.ie/discussion/comment/118938262#Comment_118938262

Hi C Eastwood,

Could I just follow up on something you've said here that's of interest to my situation?

Example 2- If you have a 100 m2 wall with 99 m2 of sound insulation- you would have very little sound reduction efficiency.

Not sure if you are talking about a single wall in a room (100m2 seems big, or entire party wall of a house over more than one level?).

We need to get sound insulation done at some stage on both sides (mid terrace). We have already sunk a lot of money into the house and reluctant to do this without knowing what results will be and also our neighbours won't be doing it either, I guess best impact would be both sides doing it..

Anyway, we had planned to perhaps do one room or one level of the house as a tester I suppose. Are you saying that this would not really be a sensible option as noise would just trickle in and down /up through the parts not done? Wouldn't be expecting miracles but more so to get an idea of whether job is then worth doing across the entire house.

C. Eastwood · 31-12-2022 8:31pm

https://www.boards.ie/discussion/comment/120049287#Comment_120049287

Hi wersal

My post you are referring to of today was taken down. Please copy and save my post here before it is taken down.

i would not have used 100 m2 for this example as it would not be logical.

In my examples I used 100 sq feet - which is approx 9.3 m2.

The point I was making is that for Insulating against sound / noise - it must be for the entire Party Wall.

A Party wall is a wall separating 2 dwellings.

Party walls constructed today must give 1 hour of Fireproofing and must also give a certain amount of soundproofing ( and I do not know this figure).

Party walls constructed with 225 mm solid concrete blocks gives excellent sound proofing. Most of these did not have floor joists build in to the Party wall.

Some of these did have some electrical sockets built in the party wall but this did not compromise the soundproofing of the Party Wall.

Older Dwellings, some with Party Walls of 225 mm solid clay bricks - also gave excellent soundproofing.

However, sometimes the First floor Joists were built in to the Party Walls from both sides, thus allowing a 60 mm x 225 mm hole through the 225 mm brick party wall at approximately 400 centres, and this allows noise /sounds to pass through the wall. These timber joists would and dried and shrunk a few mm which created gaps between the joists and mortar through the petty wall

Many Timberframe Party walls appear to be failing in relation to the Soundproofing of the Building Regulations.

There are generally 2 types of sound:-

Airborne sound:- people talking and TV and Radio etc.
Impact Sound:- people walking on floors, Doors banging etc.
Also, some mechanical ventilation systems fixed on to roof timbers in the attic, may cause vibrations in the ceilings and stud partitions on the floor below which can cause annoying noise/ sounds. This is structure borne sound.

With Party Walls -there are always neighbours at the opposite side of the Party Wall, who will generally not agree to do anything on their side of the Wall.

You need to retain an Acoustic / Soundproofing Expert to advise you on the cheapest correct methods to making your Party Walls Soundproof to the current Building Regulations.

https://www.boards.ie/discussion/comment/120031534#Comment_120031534

wersal

You referred to my Reply of today around 13.00, in which I gave free substantial Professional Advice to ‘yer man’ and it has been taken down. It took me one 1.5 hours to draft that advice to yer man.

This is unbelievable. But it does not surprise me.

I hope yer man read my advice before it was taken down.

It is a terrible shame in this forum that the people taking down free Professional Advice - do not provide the correct advice to persons seeking advice, and then remove it when it is given.

Happy New Year

C. Eastwood · 31-12-2022 8:45pm

https://www.boards.ie/discussion/comment/120031534#Comment_120031534

yer man

I poster complete professional advice to you today explaining how you could resolve the problem with the Soundproofing issues in the Party Wall of your home - at approx 13.00 and it was taken down, which is unbelievable

Before it was taken down- I hope you read it or that someone else copied it and may be able to email it to you.

Kind Regards and Merry Christmas

C Eastwood.

hilwrh9 · 30-01-2023 7:53pm

Hi All,

I am having exactly the same issue with my own home. New build 2022. Home layout appears that is exactly the same.

From looking at the regulations there must be “reasonable resistance” to sound from the unit next door.

I'm not sure if i would consider hearing my neighbours going up and down the stairs and doors closing “reasonable”. They have mentioned to us that they can hear our shower when we turn it on. doesn’t seem right to me.

I likely will have a sound test carried out in the near future. Does anybody have any idea what the might cost roughly?

Poor Party Wall Sound Isolation

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