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 email@example.com or call me direct on 07775623464.
Sound intrusion though windows can also be a source of great annoyance if the sound is excessive, and in some cases developments have failed the sound insulation testing due to poorly specified and installed windows. Sound intrusion may be down to a variety of factors. If the windows are operable types, the first thing to check is to see if the widows close properly against their seals and any weather stripping is continuous and in good order. If the window leaks air, then more often than not it will usually leak sound. If the window closes to form a tight seal and the weather-stripping seems adequate the next thing to check is the window frame. Windows are frequently installed in to the wall opening with plastic shims to insure the unit is plumb and level. In high traffic areas you will normally require a double glazed unit as a minimum and in some cases a triple glazed unit will be required.
The space between the frame and the wall should be insulated and sealed before the window casings are installed. If this was not done correctly you can probably detect the sound leakage by placing your ear close to the frame and listening. The sound may be able to run along the cavity and back into the adjacent property, It is case of letting your ears do the walking and listening. If you detect distinguishable differences in sound you may have found the problem; the solution will be to remove the casing and insulate and caulk all leaks. In some cases the thickness of the glass maybe the problem in which case it may be necessary to install another layer of glass on the inside of the existing frame making sure that the additional pane of glass is well sealed into the opening.
In some instances you may be able to lower excessive sound by installing a heavy curtain – especially if the house is in a conservation area and as a result the local authority will not let you change or upgrade the windows.