Sound insulation - New Build Semi

[simon_1975]

Hello

I would like to get some opinions and advice before I contact the housing developer of a new build home which I recently moved into.

It is a semi-detached, 3-storey home (NHBC covered). Just before Christmas our neighbors moved into the adjoining property. Although our neighbors are not noisy, we can hear a significant amount of everyday noises. For example it is possible to hear normal muffled conversations, footsteps, doors closing, toilets flushing etc. I’m sure that our neighbors will be able to hear the same from us.

The houses are separated by a cavity party wall. The plasterboard attached to the wall is the dot/dab method. It seems that the sound it being transferred really well through this wall. If I put my ear to the plasterboard I can hear normal conversation word for word (great if there is nothing on TV!)

I know that new build properties must now meet the minimum requirements as set out in part ‘E’ of the building regulations. I am going to speak to the developer and ask if the house was sound tested before completion, but I wanted to first check if what I am experiencing is normal for a new build semi or should I expect better overall sound suppression?


Thanks!

 

[^woody^]

Don't expect too much!

With a new house, particularly with painted walls (and bare or laminate flooring) then sound can be heard from adjacent rooms.

Its subjective

Design may be an issue ie toilets next to living rooms, but generally the problem wont be with the structure

 

[freddiemercurystwin]

Yea unfortunately the latest regs will not guarantee great sound insulation.

ps the developers will not have needed to have sound testing carried out if they went down the Robust Details route.

 

[simon_1975]

Thanks for the replies... Just a quick update...

I have been following this up with the building developers who are arranging a visit and to perform a sound test.

I have spoken to other people on the development who live in semi's and they tell me that they don't hear their neighbours, and their sound insulation is good, so perhaps there could be an issue with my house.

I also spoke to my neighbours on the adjoining house. They too are experiencing the same problem with noise through the party wall - so at least they can back up my claims.

I'll let you know the outcome of it all....

 

[jeds]

When sound testing became a requirement a couple of years back it was a bit unnerving for designers because we didn't know what to expect. For a bit of comfort we used to do our own ad-hoc tests such as turning a radio up full volume and shouting through the wall etc. Now, of course it was all just a bit of messing about really but, since then I've had dozens of projects tested and over the last couple of years I reckon I've got to know roughly what to expect.

For a start, you should not be able to hear normal speach through a separating wall. That's for definite. You will be able to hear loud music and you will hear shouting. But you shouldn't be able to make out what people are saying. In no project I've worked on can you make out what somebody is saying through a party wall.

There are two regimes for meeting the requirement of Part E. Robust details and sound testing. If your contractor elected for testing it doesn't mean your house was actually tested. The requirement is to test 10% of units on a site that are of the same construction. But, if it wasn't actually tested, that doesn't mean it doesn't have to meet the same standard as ones that were.

If the contractor elected for robust details then the standard of sound attenuation should, in theory, be better than under the testing regime. That's the way robust details work. The standard is much higher than normal and that should mean you get good sound attenuation even if the contractor was a bit sloppy.

Try to find out if the house was tested and if so ask for a copy of the test certificate. In fact ask for a copy anyway. Also try to find out the construction of the seperating wall. (the party wall)

If it was robust details ask for the construction details again and also ask for the inspection records which should have been kept by Robust Details. (Robust Details is a company - a bit like NHBC for sound)

Somebody might say that all big house builders use robust details and do not test. well, that's not true. Many are going for testing these days because it's clearer and cheaper.

Always, always put complaints to NHBC in writing and make it clear you do not accept the situation.

If you come to loggerheads you will have to consider your own independant sound test. It will cost you about a grand so you will need to be pretty sure there is an answerable problem to go down that route.

 

[simon_1975]

Thanks for the comments Jeds, much appreciated.
Spoke to the developers again today. The house was certified through the Robust Details route.

Regarding the party wall construction. It is a cavity party made from lightweight block. Each block wall is then screened with a dense "plaster" type material. Onto this the plaster board is attached using dot/dab method. I have been investigating some of the "Robust Details" approved construction methods and what I have seems to comply with Robust Details specifications (thats of course assuming there are no holes/cracks in the party walls, and whoever did the sign-off conducted a through inspection).

Anyway, they are coming around soon to perform the sound test so fair play to their responsiveness. They told me that if it does fail then they will carry out any remedial work. However, I understand that soundtests should be carried out in an unfurnished room as much sound is absorbed by carpets/curtains etc. So if it is a close pass I will challenge this (as mine and the neighbours houses are now fully furnished).

I'll keep you updated on the outcome...

Thanks for all the replys folks...
Simon

 

[jeds]

That's a good sign that they are taking it seriously. My guess is that the last thing they want at the moment is bad publicity.

Obviously a wall can fail for many reasons. Incorrect materials and poor workmanship is common. Poor design and detailing is also fairly common.

A brief story about robust details: My brother is a contract manager for a large housebuilder. They were paying hundreds of thousands a year to robust details. About 18 months ago they decided to try sound testing instead - the cost saving is very significant. A site was chosen and they prepared the houses. It would have been too much to redesign the houses so they decided to stay with the original method of construction. i.e. the robust detials.

In theory this should mean that the sound test would be well in excess of the minimum standard. Well it wasn't. They only just scraped through. Literally they only passed the test by a fraction. They were - to use a technical term - gobsmacked. These houses were built to robust details and they made sure every detail was exactly as specified. My bro admits this is not true of all houses.

 

[simon_1975]

Hello again – here is an update…

The developers have been around and conducted a sound test. I was mailed the results and the particular room tested passed by 4dB (total reduction was 49dB, the required minimum is 45dB).

So it would seem that part E of the building regulations does not guarantee a quite home. I have lived in several semi-detached houses, one was built in the 50’s and the other was built in the 80’s. These older houses were much better, I never really heard my neighbors.

My current neighbors were as shocked as me when the results arrived as they too agree the sound insulation is very poor. Fortunately my neighbors are considerate (like me) and keep noise to a minimum, but even then I can still hear normal muffled conversation, TV’s footsteps on stairs etc. (The impact noise is the worst, such as doors closing / footsteps etc).

So buyers of new semi’s beware! Don’t assume that part E will give you a quite home.

Next time I will buy a detached for sure!

Thanks for all of your past comments…