Sound Testing in Flats

We have undertaken thousands of sound tests on many types of projects that that require sound testing such as blocks of flats, HMOs and semi-detached houses. These may be new build or conversion projects, such as an existing office which has been converted into flats.

There is lots of useful information within a section in Building Regulations called “Approved Document E” this document provides details on the building regulation in England and Wales for the resistance to the passage of sound and sound insulation for flats, houses and rooms for residential use.

It can be hard to know how you need to prepare your development, to try and help our clients to prepare for their sound testing we have prepared our Sound Testing Checklist.

How Many Flats need to be Sound Tested?

Approved Document E states “Building control bodies should stipulate at least one set of sound tests for every ten dwelling houses, flats or rooms for residential purposes in a group or sub-group” – but this is more complex than it seems at first glance, and is often wrongly interpreted as 10%. If the flats on the development have several different construction types, you may need more than the one set of tests in ten stated above.

For instance a group can be determined by the type of dwelling, so houses, bungalows, flats are all different and should be treated separately for the number of tests. For instance of you have a pair of semi-detached houses and a block of 6 flats the development should require the following testing:

  • 2 airborne wall tests to the semi-detached houses
  • 2 airborne wall tests to the flats
  • 2 airborne floor tests to the flats
  • 2 impact floor tests to the flats

Sub groups can be quite complex and we advise letting us looking at each project individually to establish whether your project’s construction type means you’ll need additional testing. APT sound testing are always happy to take a look at your project on an individual basis to help ensure you are booking the correct number of tests to ensure compliance with Approved Document E.

What rooms require sound testing in flats?

Approved Document E also specifies which rooms need to be tested. Sound testing is required between living spaces, which usually includes:

  • Living room
  • Bedrooms
  • Study
  • Dining room
  • Kitchen

Although there is no requirement to test between common areas such as stairwells, corridors and hallways, if no suitable rooms are available then building control may insist that a test is carried out between a stairwell and bedroom and/or a bedroom and bathroom.

Preparing Floor for Sound Testing in Flats

One of the keys to securing a sound test pass is ensuring that everything within the building is set-up correctly. We’ve put together this comprehensive list detailing which parts of the property need to be prepared in advance:

1. The whole building envelope and internal walls and floors should be fully completed
2. All window and doors must be fitted and working correctly. A substantial amount of noise can leak through any gaps and can have a negative influence on the final test results.
3. All electrical fittings must be completely in-place, and fully functional. Poor electrical installation such as missing sockets/faceplates down lighters etc. can lead to excess noise.
4. No carpets or laminated flooring should be fitted on the 1st floor levels or above. These materials can affect the movement of noise, and as a result could impact on whether a building passes the sound check test.
5. 240 volt power should be in-place and available in every room. Our testing equipment can be damaged by the voltage fluctuations of on-site power generators, so it’s essential to have 240V mains supply on-site on the day of the test
6. The building skirting should not touch the floating floor and flanking strips used as and where required.
7. All gaps in the walls and floors should be sealed with acoustic mastic etc. Noise can leak out through any gaps and affect the movement of sound and impact on the sound insulation performance.
8. Access to all of the rooms on all levels should be granted to our technicians – also in occupied neighbouring properties where required. All site noise sources such as building work, radios and fire alarms should be stopped for the duration of the test.

The above points are all essential if we are to achieve accurate sound test readings.  If any of them are ignored, there is a risk of you either failing your test or – at worst – not being able to complete it, at which point you may still be charged 75% of the test fee.

All doors and windows must be fitted and working correctly. A substantial amount of noise can leak through any gaps and influence the test results.

Preparing Walls for Sound Testing in Flats

1. The whole building envelope and internal walls and floors should be fully completed
2. All electrical fittings must be completely in-place, and fully functional. Poor electrical installation can lead to excess noise.
3. 240 volt power should be in-place and available in every room. Our testing equipment can be damaged by the voltage fluctuations of on-site power generators, so it’s essential to have 240V mains supply on-site on the day of the test
4. No carpets or laminated flooring should be fitted on the 1st floor levels or above. These materials can affect the movement of noise, and as a result could impact on whether a building passes the sound check test.
5. The building skirting should not touch the floating floor.
6. All gaps in the walls and floors should be sealed. Again, noise can leak out through any gaps, affecting the movement of sound and impacting on the space’s performance.
7. Access to all of the rooms on all levels should be granted to our technicians, with all noise sources (radios, alarms, building work) ceasing for the duration of the test.
8. The above points are all essential if we are to achieve accurate sound test readings. If any of them are ignored, there is a risk of you either failing your test or – at worst – not being able to complete it, at which point you may still be charged 75% of the test fee.

Acoustic floor upgrade for passing sound testing on Existing Flats

To reduce airborne and impact sound transmission this usually means adding density and isolation to the floor construction. This can be as simple as adding a drop ceiling consisting of 125mm timber frame. The top of the frame must be a minimum of 25mm below the existing ceiling finish – such as lathe and plaster. Then, to the inside of the timber frame add 100mm of Acoustic Wool and two layers of sound-board tacked to the bottom of the timber frame – all boards to be lapped. This should improve your sound test results by approx. 15dB depending on the existing site conditions and quality of the installation.

Acoustic wall upgrade for passing sound testing on Existing Flats

One way to quick and simple way improve the acoustic performance of a dividing wall partition, is to install a 70mm met-sec partition in front of the existing wall – it’s usually best to install this in the largest room. Leave approx. 25mm gap between the back of the met-sec and the wall. Then install 50mm acoustic wool to the inside of the met-sec and add two layers of 12.5mm soundboard to the outside of the met-sec frame, ensuring all boards are properly lapped and the perimeter joints are filled with acoustic mastic – Detail 3 shows this in more detail.

The main design considerations for wall and floor partitions to Flats

To improve the chance of a successful sound test and reduce the chance of noise flanking you will need to ensure that you allow for the following five acoustic design considerations, when upgrading an existing floors and walls in flats they are:

a. Mass
b. Isolation
c. Absorption
d. Resilience
e. Stiffness

We can advise on all types of acoustic design, whether it’s accomplished during initial construction or during a refurbishment/renovation project. We also undertake UKAS accredited sound testing providing a ‘one stop’ solution for all your acoustic requirements.

If you would like more information in regards to sound testing please contact us at info@aptsoundtesting.co.uk or call Darren Direct on 07775623464.

Alternately, if you would like more information on how to prepare for your sound testing please download our sound test checklist.