Avoiding Acoustic Failures in Building refurbishment and Retro-fit

Penny Dixon 23 April 2024

Sound is an omnipresent aspect of our lives, influencing our health and well-being. A recent seminar presentation by KP Acoustics shed light on the complexities surrounding acoustic failures within existing buildings and their refurbishment. As we navigate through the intricate world of acoustics, this article will explore key insights from the presentation, addressing the impact of noise on human tolerance, the vulnerabilities in building structures, and the imperative need for a holistic approach in refurbishment projects.

The seminar began by highlighting the pervasive nature of sound, emphasising its ubiquitous presence in our daily lives. However, the focus shifted to the detrimental effects of noise on health and well-being. Noise pollution has been linked to various health issues, including stress, sleep disturbances, and reduced cognitive performance. Understanding the intricate relationship between sound and its impact on occupants became a pivotal starting point in the discussion.

The presentation delved into the science of sound, illustrating how sound waves interact with surfaces. Some waves are absorbed, while others are reflected, leading to the phenomenon of reverberation. The challenge arises when excessive reflected sound causes prolonged echoes, negatively affecting the acoustic environment. A crucial aspect in refurbishment projects involves addressing reverberation through a strategic balance of absorption and reflection.

The historical context of acoustic standards, particularly Part E, was discussed. While Part E was once deemed effective, the current perspective reveals a shift toward targeting the minimum level of human tolerance. This change underscores the need for a more nuanced and comprehensive approach to acoustic design and refurbishment, considering the evolving understanding of our tolerance to noise, particularly in a post-COVID era.

Identified as the most significant source of noise, impact noise poses a formidable challenge in building acoustics. The presentation emphasised the vulnerability of flanking, particularly through continuous slabs where partitions fix up to the underside. The weakest points in a structure were highlighted, necessitating robust solutions to mitigate the impact of noise transmission through these vulnerable paths.

An intriguing revelation from the seminar involved the phenomenon of Aeolian tones, which are caused by turbulence from a specific direction and the resonance of balustrades on balconies. The presentation discussed real-world instances of noise disturbances caused by whistling balconies on buildings. Remedial measures, including the addition of spoiler fins, were explored to tackle this specific acoustic challenge.

The seminar emphasised that each space possesses its unique acoustic identity. Achieving optimal acoustics requires a nuanced understanding of diffusion and absorption. Strategic placement of diffusers and absorptive materials emerged as essential elements in creating an acoustic environment that aligns with the intended purpose of the space.

The discussion turned to the critical role of workmanship in acoustic performance. Compromising resilient bars, which decouple wall linings from studs, was identified as a significant concern. Even a minor compromise can result in a loss of 4 dB in acoustic performance. The importance of attention to detail, particularly in the installation process, cannot be overstated.

A case study involving a masonry wall highlighted the disparities between the achieved dB levels and compliance with Building Regulations (BRegs) Part E. While the masonry wall alone achieved 38 dB, which fell short of compliance, decoupling strategies pushed the performance to 49 dB. Identified issues included mortar gaps and unsealed penetrations, reinforcing the importance of meticulous detailing in acoustic design and refurbishment.

Flanking issues were addressed in the context of party walls meeting external walls. To avoid typical flanking problems, it was emphasised that party partitions need to be slab to slab. Additionally, services, when exposed, were identified as potential contributors to noise transmission. Lagging services, especially where they are exposed, emerged as a necessary measure to mitigate flanking issues.

Floating floors, while offering benefits in terms of acoustic isolation, present their own set of challenges. Resilient pads were discussed as crucial components in decoupling the floor from the slab. However, the importance of these pads being designed by specialists was underscored to ensure optimal performance and prevent failures.

The seminar concluded by highlighting that acoustic failures can occur at all stages of a building project – planning, design, and construction. It emphasised the need for a holistic approach, where acoustic considerations are woven into every aspect of the project lifecycle. The importance of recognising the entire floor as an amplifier further emphasised the necessity of decoupling strategies at the design stage to prevent acoustic failures.

In conclusion, there are many challenges associated with acoustic failures in existing buildings and their refurbishment. From understanding the nuanced science of sound to addressing the vulnerabilities in building structures, the insights provided hi-lighted the need for a comprehensive approach. As we navigate the evolving landscape of retro-fit and the acoustic standards required, a commitment to meticulous planning, resilient design, and impeccable workmanship will be pivotal in ensuring acoustic success in refurbishment projects.