Sound Insulation on London Properties
Improving Sound Insulation on London Properties
Many of the dwellings in London consist of flats converted from large Victorian houses. Unfortunately at the time of the building conversion, designing for sound insulation was not a high priority and so many of the dwellings suffer from adverse noise transference between the floor and wall partitions. This can be extremely stressful to the occupant’s wellbeing is a major cause for concern.
There are ways to improve the airborne and impact performance by improving the wall/floor partitions ability to reduce the amount of sound transmission from one side of a construction element to the other. By isolating the different materials may not be enough its own and you may need to improve the mass of the partition as well.
Improving Existing Floor Partitions
In our experience of undertaking hundreds of sound tests in London, refurbishment projects usually achieve 30-35dB for airborne sound and 70dB for Impact Sound, if the existing construction has not been acoustically upgraded. These figures do not meet the required 43dB & 64dB as stipulated in Part E of Building Regulations. As sound double every 10dB this is a massive failure and acoustic improvements must be made. Many existing construction consist of a similar construction as shown in as detail 1 below.
Detail 1: Existing Floor Partitions Rated At Approx. 30dB
Acoustic Improvements to Existing Floor Partitions
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. 10-15dB depending on the existing site conditions and quality of the installation.
Improving Existing Wall Partitions
The standard onsite construction for existing internal walls may be a mixture of 100mm masonry with render applied to either side; or, 100mm timber partition with lathe and plaster to either side. Unfortunately neither of these existing wall constructions will have the acoustic properties to pass Part E in their existing state due to lack of mass and poor isolation values.
Improving Wall Partitions
One way to quick and simple way improve the acoustic performance of a the dividing wall partition, is to install a 70mm metsec partition in front of the existing wall – its usually best to install this in the largest room. Leave approx. 25mm gap between the back of the metsec and the wall. Then install 50mm acoustic wool to the inside of the metsec and add two layers of soundboard to the outside of the metsec frame, ensuring all boards are properly lapped and the perimeter joints are filled with acoustic mastic.
Taking the above into account is it essential that the acoustic design is addressed right from the start of the refurbishment project, so it prevents delays in handover, i.e. to prevent the dwelling failing the sound testing at building control signoff stage – a common problem.
We can also offer acoustic design advice and UKAS sound testing on existing flats to ensure that the building handover is not delayed due to noncompliance with Part E. We can also undertake sample sound testing on projects where clients are worried about existing ‘hybrid’ construction/s to help highlight the existing noise levels so acoustic upgrades – if required) can be quickly targeted and implemented.
If you would like advice on your acoustic design or require sound insulation testing in London, please contact us now on 07775 623464 or contact us at info@aptsoundtesting.co.uk.