“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

Noise-related changes to the General Permitted Development Order

Recent amendments made to The Town and County Planning (General Permitted Development) (England) Order 2015 will have a significant impact on how developers approach Class O (office to residential) permitted developments.

In a move that was widely expected by many in the industry, The Permitted Development order has now made permanent the existing rights to convert existing offices buildings for residential use. However, an additional criterion has been added, stating that the Local Planning Authority (LPA) must consider the ‘Impacts of noise from commercial premises on the intended occupiers of the development’ when assessing applications. Previously this was not a consideration and there was no mechanism in place for LPAs to refuse applications on noise grounds.

The reason for this criterion is principally as a result of campaigns on behalf of licenced premises and two specific documents: the ‘London Grassroots Music Venues Rescue Plan’ and the ‘Bristol Live Music Census Report’. Both reports and the campaigns cite that the permitted conversion of offices into residential properties have resulted in noise sensitive receptors (i.e. residents) being introduced into areas where there are long established music venues or other sources of noise. This, in turn, has given rise to noise complaints from the new residents and the LPA imposing additional constraints on the music venue or noise source. This is seen as unfair and a potential threat to the night time economy of the UK.

Although the requirement to assess noise impact has been welcomed by campaigners, this move falls short of the ‘Agent of Change’ principle which had been campaigned for. The agent of change principle seeks to place the responsibility for noise mitigation measures on the incoming noise sensitive use, not the premises generating the noise.

It should be noted that although the wording of the amendment does not oblige the LPA to apply the Agent for Change principle, it does not preclude it either. The lack of clarity has been highlighted in a recent debate in the House of Lords in which ministers were called upon to provide further guidance. It will be interesting to see what further information is provided in the coming months.

The discussion surrounding noise and permitted developments touches on a wide range of legal and ethical questions, and the answers may not be as straightforward as they seem. For an interesting summary of relevant case law (and their implications) please see http://www.noisewise.com/the-agent-of-change-principle-noise-from-music-venues-and-recent-case-law/.

Given the lack of clarity in the guidance, it is advisable for developers to contact the Local Authority prior to submitting a Class O permitted development application to fully understand their requirements with respect to noise.

If you have an upcoming Class O permitted development application and you are concerned about these recent changes to legislation, please get in contact with Patrick Allen (patrickallen@cassallen.co.uk, 01234 834859) or Chris McNeillie (chrismcneillie@cassallen.co.uk, 01234 834872) and we would be happy to help you further. Cass Allen has extensive experience in the assessment of commercial noise sources impacting on residential developments. For examples of our work please see www.cassallen.co.uk.


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