Posted: 22nd February 2022

Why is sound insulation an essential consideration when developing houses and flats?

It is essential that sound insulation is carefully considered when developing houses or flats.  Complaints about excessive noise and nuisance is the most common cause of dispute between residents.

To control noise between dwellings, all new residential properties must comply with The Building Regulations Approved Document E.  This aims to ensure a ‘reasonable’ standard of sound insulation between dwellings.


Approved Document E: an overview

Building Regulations Approved Document EApproved Document E: Resistance To The Passage Of Sound is divided into four sections covering the following aspects:

  • E1: Protection against sound from other parts of the building and adjoining buildings.
  • E2: Protection against sound within a house/flat.
  • E3: Reverberation in the common internal parts of buildings containing flats or residential rooms.
  • E4: Acoustic conditions in school.

Requirement E1 primarily relates to sound transmission to residential properties.  This includes adjacent dwellings as well as adjoining commercial or communal areas.  Minimum performance standards are set which normally should be demonstrated by testing on site.

Requirement E2 sets minimum standards for internal walls and floors within a dwelling. Unlike E1, these are laboratory tested values and selecting a suitable construction method is considered acceptable.  Requirement E3 ensures that there is sufficient acoustic absorption in the common areas of blocks of flats.  Finally, E4 sets a legal requirement for the acoustic conditions in schools to be appropriate for the intended use.

The guidance applies to new-build properties and buildings undergoing a conversion (“material change of use”).  In certain it may also be necessary to comply with ADE when undertaking alterations to existing residential properties.

Sections 2, 3, and 4 of Approved Document E provide example constructions for separating walls and floors.  When properly designed and installed, these should be suitable to achieve the minimum performance standards.


Approved Document E: the minimum expected standards

It is important to remember that Building Regulations specify the minimum standards that a building must achieve to be considered suitable for habitation.  The performance criteria outlined in Approved Document E provide a minimum reasonable performance.  These must be achieved when any new-build or conversion residential project is undertaken.

In some circumstances, it will be appropriate to implement measures that achieve a higher specification of acoustic insulation.  This could be the case when a development is aiming to achieve BREEAM credits.  Some Local Authorities include planning conditions which require a higher standard.  For high end developments, the developer may also simply with to provide better quality dwellings for future owners and occupants.


The problem of reverberation

Reverberation is another word for ‘echo’: the reflection of a sound from a hard surface. High levels of reverberation can be disorienting or distracting as the sound ‘overlaps’ with the original sound.  This can be particularly noticeable in large entrance foyers or multi-storey stair cores to residential apartment blocks.

Approved Document E provides two methods to demonstrate a development will incorporate sufficient acoustic absorption in communal areas.  The simplified Method A requires a minimum area of acoustic absorption to be included.  Method B uses a calculation procedure to determine the amount of absorption required.  This can allow greater flexibility than Method A.


How a qualified acoustic consultant can support your residential construction project

Complying with Approved Document E is vital when undertaking a residential building project.  The costs of rectifying failed sound insulation testing can be significant, particularly as they come at the end of the project meaning redecoration, kitchen or bathroom fittings could have to be removed and refixed, or when they might hold up the sale of the new properties.

A professional acoustic consultant will be able to advise whether your building’s construction methods and flanking and junction details will be suitable to meet the required standards. They can also ensure that the proposed construction details are the most suitable and cost-effective.  Often ‘acoustic’ products are not necessary and standard building products would be sufficient or even provide a better standard of sound insulation at a fraction of the cost!  Employing a qualified acoustic consultant early in the design stage can save £000’s and give you peace of mind.


ACA Acoustics’ design review service

At ACA Acoustics, we can provide an acoustic design review of your development and then undertake pre-completion sound insulation testing required by Building Control for your development:

  • Acoustic design review: We will review your layout drawings, proposed construction details for separating walls, floors, junctions, and flanking elements.  If necessary 3D computer modelling and specialist acoustic software can be used to identify potential areas of concern and to develop appropriate mitigation measures.  When an existing building is being converted into residential flats it is sometimes beneficial to carry out preliminary tests on the existing construction.  This way you know what your starting point is, and if the existing structure even already complies with Approved Document E.  This can save you from doing further works and save money in the long run.
  • Pre-completion testing: once construction is finished, sound insulation tests are conducted between adjoining houses or flats.  Test results are compared against the requirements of Approved Document E.  The tests must be carried out by a qualified acoustic consultant with an appropriate accreditation, such as UKAS, ANC, or SITMA.  ACA Acoustics are accredited through the SITMA registration scheme.


How to choose your sound testing company

Sound testingWhile the cost of the tests may be a factor when choosing a sound insulation testing company, it’s vital to select an acoustic consultancy who has experience of providing design advice.  Getting the correct advice at the earliest stages of development planning and during construction which can far outweigh any minor savings that could be achieved for the tests alone.

The acoustic consultant should also have the knowledge to be able to offer appropriate guidance on remedial work should the airborne or impact sound insulation tests fail.


What is the Robust Details scheme?

For new properties, developers can register with the Robust Details scheme.  The developer must then construct the building to an approved build-up.  These Robust Details have been proven to achieve the correct level of acoustic insulation.  Robust Detail Assessors conduct site audits to ensure compliance.

If there are non-standard junction details or the site audit identifies that the Robust Detail has not be strictly adhered to then pre-completion sound insulation testing would be required.  ACA Acoustics can review whether any deviation from the Robust Detail is likely to affect the test results, offer advice on remedial works if necessary, and undertake the pre-completion sound insulation tests.


What about Approved Document O?

As well as complying with Approved Document E, new dwellings also need to comply with the noise limits to bedrooms specified in Approved Document O.  This considers if noise levels in bedrooms will be excessive when windows are open to mitigate overheating at night.


Contact ACA Acoustics today

To find out more about our acoustic consultancy services to ensure your residential building project complies with Approved Document E of the Building Regulations or to book in your sound insulation tests, please get in touch today.


Image Source: Unsplash

Posted By:ACA Acoustics