Soundproofing a Semi Detached - Advice/ Experiences

[cwcw]

Hi all,

We live in a 1930s semi-detached house with the living room and bedrooms adjoined in a mirror image. The living room is one single, large through room (not two knocked through to one, but built that way) with a single fireplace on the party wall. The party wall, based on the exposed wall in the loft, seems to be double skin with no cavity. Our fireplace is open with a gas fire, and looking up the chimney flue from the open fire it is exposed brick with patchy/ deteriorating mortar. To either side of the chimney breast are two large alcoves.

Until a few years ago we had really quiet, elderly neighbours and assumed the party wall was very well built and we just couldn't hear each other. Then a new family bought it and it seems the soundproofing is actually really bad (and the previous couple probably heard a lot more of us than we thought!). The new family aren't noisy or inconsiderate by any stretch - quite the opposite. Yet we are getting to hear all kinds of noise through the party wall, particularly the living room but to a lesser extent the bedroom (baby crying). If there is no other noise in our house, we can basically hear conversations going on through the living room wall, as well as the dog whining and barking if they nip out and leave it, and the baby crying. It seems to have got worse recently as they have had work done and I suspect had carpets removed for wooden flooring. It has got to the point where I want to do something about it.

As it is a large room we could comfortably lose 5 inches in the alcoves to fit some kind of false wall or other insulation. My concern would be, would this be worth doing or would the sound continue to travel through the chimney flue wall? It is a fairly new fireplace so ripping it all out to work on the inside of the flue would be a big job and beyond my DIY skills, but sorting out the alcoves would be much more achievable. I'd also look to go below floor level and add further insulation there. When I can hear noises I have been trying to work out where the weak points are and it definitely comes through the alcove walls, but I can't say for sure it doesn't come through the chimney flue too.

Hoping for any views on what is possible and how much I have to do to achieve a reasonable result? I don't expect to block out all sound, but to not be able to hear day to day noises like conversations.

Thanks in advance.

 

[^woody^]

You'll have great difficulty, as the sound needs to be stopped getting out from next door, and not stopped getting in from your side.

Apart from dealing with any gaps around joists in the party wall, you will have have little success with insulating the party wall.

 

[motorbiking]

You need to track down where the sound is coming from, It could be you have connecting joists which allow the sound to be transmitted. The next option is to consider if you can position furniture close to the source to absorb the sound.

 

[cwhaley]

I dread this day. Lived next to a lovely old lady for nearly six years. I have poor hearing but can hear her coughing, the carers talking to her and the phone ringing. We have concrete floors downstairs and solid brick walls, so I accept there's nothing reasonable we can do and will just have to accept any increases in future noise.

A friend of mine lives in a '50s house built to the '30s design with wooden floors. Insulating between the floor joists and laying thicker carpet made a big difference. My parents insulated their outside walls about 20 years ago and it made the living room much warmer but made little difference to sound 'ingress' from outside.

 

[conny]

If you are going to try to 'sound' insulate there are special boards you can buy, as opposed to normal insulation boards such as cellotex.
Installed correctly they will give excellent results. The downside is they tend to be very expensive for good quality ones. As stated above, you will also need to stop the sound getting in through other sources such as the joists.

Here is an example of the kind of thing I'm talking about. I can't say if these are good, as the ones used in my workplace are excellent but cost a great deal more, but I can't remember the name of them at the moment.

40mm EcoTherm Eco-Versal PIR Rigid Insulation Board

 

[cwcw]

You'll have great difficulty, as the sound needs to be stopped getting out from next door, and not stopped getting in from your side.

Apart from dealing with any gaps around joists in the party wall, you will have have little success with insulating the party wall.

When you say little success though, do you mean I'd still likely hear noises, or still be able to hear conversations, coughs, sneezes etc like now? At this point, any reduction in sound seems like success.

 

[cwcw]

You need to track down where the sound is coming from, It could be you have connecting joists which allow the sound to be transmitted. The next option is to consider if you can position furniture close to the source to absorb the sound.

Furniture positioning maybe an option upstairs (wardrobes) not not really for the living room. It's difficult to tell for sure all of the places where noise is coming from but it does sound like directly through the walls is at least one source.

 

[^woody^]

When you say little success though, do you mean I'd still likely hear noises, or still be able to hear conversations, coughs, sneezes etc like now? At this point, any reduction in sound seems like success.

By little success, I probably mean virtually no success.

Sound travels through air (gaps in the structure) and then the actual structure. So once you seal gaps as best you can, you need to stop the sound getting into the structure rather than getting out of it.

So whilst you can line your room, that will benefit the neighbours more than you. Also you should not just randomly line the structure and hope for the best, as sound proofing really needs to be designed. Then comes the cost/benefit and benefit/disruption factors.

Yes, people will say you could have a front room like a sound studio, but then the issues are at what cost, and at what disruption to the living space?

 

[Lower]

When you say little success though, do you mean I'd still likely hear noises, or still be able to hear conversations, coughs, sneezes etc like now? At this point, any reduction in sound seems like success.

There's loads you can do, but you'd need a professional noise insulation company to do it for you. However, don't expect to achieve zero noise transmission from your neighbours.

Its quite involved, but plenty can be done. We fit silencing to the equipment that we manufacture. It's amazing what can be done with the right materials in the right places that absorb the sound rather than transmitting it or reflecting it.

 

[seasider]

We’re in a terraced house and had similar issues with students. Fortunately we had enough room in the first floor bedrooms to lose 20cm. We built stud wall, not fixed to party wall. Filled with sound proof insulation. Double boarded with soundproof board and filled any gaps with sound proofing mastic. No longer hear them talking but bassier noises carry like heavy bass on music, doors slamming, heels on tiled floors. But it is a massive improvement and well worth it. We got materials from SIG insulation.

 

[cwcw]

We’re in a terraced house and had similar issues with students. Fortunately we had enough room in the first floor bedrooms to lose 20cm. We built stud wall, not fixed to party wall. Filled with sound proof insulation. Double boarded with soundproof board and filled any gaps with sound proofing mastic. No longer hear them talking but bassier noises carry like heavy bass on music, doors slamming, heels on tiled floors. But it is a massive improvement and well worth it. We got materials from SIG insulation.

That's the sort of thing I'm starting to look at. I've found a solution that would be a stud wall and would only take about 14cm of room away, but my concern is still with the chimney flue because it's impossible to sound proof inside that. Did you have anything like that or just a flat wall?

 

[seasider]

Yeah both rooms we did had a chimney breast so stud wall went all the way across mirroring shape of the wall. Again not fixing to the actual chimney breast. One room we used metal studs, the other timber. Tbh, room with timber seems to have worked better.