Why Have I Failed my Sound Insulation Test?

Why Have I Failed my Sound Insulation Test?

This is one of the most common questions clients ask when their property has just failed the sound testing. One of the main reasons for acoustic partitions failing the Part E sound test is often down to poor isolation of material/s, which can lead to excessive noise flanking. Noise Flanking is a term used by acoustic engineers to describe where sound passes through an acoustic partition due to the abutment of materials. The noise simply hits the one side of the wall and then travels through the construction via a noise bridge. This can be areas such as the incorrect use of masonry wall ties i.e. solid fishtail ties, used in place of specified acoustic wall ties; if your building suffers from noise flanking it may result in a sound test failure.


Unwanted noise travelling along flanking paths can make the building structure vibrate, which can cause sound to radiate into your room – as shown in the plate below . One simple cost effective solution is to build another wall or ceiling in front of the original, to offer extra isolation. For this upgrade to work you need to make sure that the independent wall or ceiling is not directly connected to the existing failed partition; so it provides isolation between materials.


Noise flanking can also be down to the use of down to the use of lightweight blocks in the construction of the building envelope. Due to the lightweight mas of the inner wall it allows sound to transmit from dwelling to another, both vertically and horizontally. If a building has failed its sound testing, it is essential to establish if the problem is due to direct transmission, flanking transmission or a combination of both so that the most cost and time effective remedial treatment can be designed and applied to the failed partitions.

If you require more information about acoustic design and/or sound testing on your project, please contact us now at info@aptsoundtesting.co.uk or call me direct on 07775623464.