“Very proactive and extremely helpful, especially with technical queries. I would not hesitate to recommend and will certainly be using them again in the future.”



Under CDM2015 regs we have found CASS ALLEN to exercise a level of professionalism and due diligence which is second to none. We would therefore definitely recommend CASS ALLEN as our preferred acoustic consultant, for all of our projects.’


SF - Taylor Wimpey South Thames

“I was very pleased with their technical knowledge and professional approach when dealing with a very awkward purchaser as well as the local authority.”


JH, Telford Homes

“Cass Allen went above and beyond to help with the Acoustic planning performance and conditions regarding the Greenwich Creekside project…”


LM, Capita plc

“Good comprehensive reports and advice at all design stages. Very flexible and professional, provided attendance at acoustic cladding tests at short notice.”


DF, Berkeley Homes

“Cass Allen have assisted us on a number of our projects. I’ve been impressed with their thorough and professional approach.”


MT, Lark Energy

Guide to noise barriers

Noise barriers, or acoustic screens, are commonly used to reduce the effect of noise from roads, rail and industrial sources on residential properties. In particular, they are often required by local authorities to achieve recommended noise levels in external areas, including gardens and communal amenity spaces.

In order for noise barriers to be effective, they should achieve the following criteria:

  • Barriers must be generally imperforate. Hit and miss fencing, slatted fencing or foliage are not effective noise barriers as sound passes through the gaps.
  • Barriers should have a minimum mass of 10 kg/m2. Noise may pass through lighter weight materials.

For masses above 10kg/m2, the sound reduction provided by a noise barrier is unlikely to improve. The performance will be limited by sound diffraction over the top of the barrier. Therefore, a 10kg/m2 close-boarded timber fence will normally provide the same noise reduction as a 100mm concrete wall. Be careful if suppliers are recommending heavier noise barrier options for acoustic reasons, as these reasons may be false. Call us for an impartial view.

Set out below are common architectural screening options with comments on their acoustic effectiveness. It should be noted that, although some options will provide limited reduction in actual sound levels, any sort of visual screening has been shown to provide a subjective acoustic benefit – people are less bothered by a noise source that they cannot see!

Combinations of different barrier types are often also used for aesthetic or practical reasons. For example, an acoustic fence could be used on top of an earth bund where there was a requirement for a very high barrier (this is a particularly cost-effective option for sites where there is a lot of earth spoil which would otherwise have to be transported off site), or a green screen could be used in front of a brick wall for a more attractive aesthetic.

Cass Allen are experienced in the design and specification of noise barriers. Please let us know if you would like more information.



Get in touch

We hope you’ve enjoyed browsing our website but if you have any questions feel free to call us to talk through any acoustic issues you may be facing on your projects. The best person who can help with specific queries can be found here.