Posted: 22nd February 2022

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

When developing houses or flats – either new build developments or where existing buildings are converted into dwellings, it is essential that sound insulation between the dwellings is carefully considered.

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. However, complaints about excessive noise or nuisance is an ongoing issue for Local Authorities and a common cause of disputes between residents.


Approved Document E: an overview

Approved 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, either from adjacent dwellings or from adjoining commercial or communal areas. Minimum performance standards are set which 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 aims to ensure that sufficient acoustic absorption is incorporated into 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, buildings undergoing conversion (termed ‘a material change of use’, examples include offices being repurposed as flats, etc.), and in certain cases for alterations to existing residential properties.

Sections 2, 3, and 4 of Approved Document E provide example constructions for separating walls and floors that, when properly designed and installed, should be suitable to achieve the minimum performance standards.  However, it is important to remember that your Building Control Officer will consider whether the pre-completion sound insulation tests on site ‘pass’ the Approved Document E 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 measures outlined in Approved Document E are designed to provide a minimum reasonable performance and, therefore, must be adhered to when any new-build or renovation residential project is undertaken.

In some circumstances, it will be appropriate to implement measures that achieve a higher specification of acoustic insulation that go far beyond those outlined in Approved Document E.  This could be the case when a development is aiming to achieve BREEAM credits, if required by a Local Authority planning condition, or simply where a developer aims to provide high 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, particularly in communal areas of residential properties, such as large entrance foyers or multi-storey stair cores.

Approved Document E provides two methods to satisfy Requirement E3; the simplified Method A, which requires a minimum area of acoustic absorption to be incorporated into entrance halls, corridors, and stairwells.  Method B uses a calculation procedure to determine the amount of absorption required and 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.

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. At times 3D computer modelling and specialist acoustic software can be used to identify potential areas of concern and to develop appropriate mitigation measures. Where an existing building is being converted into residential flats it is sometimes beneficial to carry out preliminary tests on the existing construction, so you know what your starting point is, and if the existing structure even already complies with Approved Document E, saving you from doing further works.
  • Pre-completion testing: once construction is finished, sound insulation tests are conducted between adjoining houses or flats to demonstrate that the requirements of Approved Document E have been met. 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.
  • Robust detail: for new properties, developers can register with the Robust Details scheme. The developer would then construct the building to an approved build-up, proven to achieve the correct level of acoustic insulation, with audits conducted to ensure compliance.  However, 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.

While 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, both 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.


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