“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 reverberation control

The guide is aimed at developers and architects and sets out common reverberation control treatment options for rooms.

These treatments are used to prevent excessive reverberation and are often required to achieve acoustic specifications or regulations. In particular, reverberation treatments are required for the following development types:

• corridors in residential developments to comply with Building Regulations Part E
• teaching rooms in schools to comply with BB93 (as required by Building Regulations Part E)
• rooms within medical or healthcare facilities to comply with HTM08-01
• office workspaces (particularly open-plan workspaces) to achieve good quality work environments

The amount and type of treatment will vary depending on the size and use of the room. In many cases, the location of the material is also very important.

The performance of acoustic treatments is graded based on the amount of sound they absorb. The best absorbers are Class A (almost total absorption), however, Class B & C absorbers are also very effective.

Set out below are a number of common treatments along with their pros and cons.

Acoustic ceilings and wall panels

Perforated plasterboard


Mineral tile


metal tile


acoustic plaster


spray absorption


hanging raft


vertical baffle


wall panel


Other treatments



soft furnishing

As shown above, there are various treatment types, many of which also come in different styles and configurations. The key is finding the right treatment (or combination of treatments) for every project. Cass Allen has extensive experience in the design and specification of reverberation treatments including numerous products and suppliers. 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.