De-tuning of Whistling Brise Soleil

Residential • Environmental • Expert Witness • Modelling • Awards

This is the story behind this fascinating and ANC award-winning project which involved transforming a 1960s six-storey office block into a stunning modern landmark.

The project added a new floor of luxury penthouse apartments and crowned the building with a signature ring of brise soleil. This striking architectural feature wasn’t just for show bringing solar shading and a modern appearance.

When the scaffolding came down, an unexpected challenge arose: a mysterious whistling sound was heard and quickly became the talk of the community. The local council began evaluating the situation under the Environmental Protection Act (EPA).

Our mission was clear: pinpoint the source of the sound, understand the exact conditions that caused it, and deliver a swift, effective solution to “make it go away”.

We searched globally for similar issues and surprisingly found a lot to work with, countless stories of new buildings where there had been complaints about whistling sounds.

It was clear we were going to have to navigate the technical complexities of aeroacoustics, work with limited roof access, in inclement weather, to tight timescales, and with a need for both visual appeal and cost-efficiency. Immediate action was critical to protect the amenity of locals and residents and avoid further action from the local council.

Our process was data-driven and thorough. We deployed advanced noise-monitoring system with a weather station, correlating wind patterns and sound levels. Our investigation revealed that the whistling originated from select sections of the brise soleil, which were triggered when roof-level wind speeds hit 10 m/s. The wind created a clean1300 Hz tone reminiscent of a finely tuned musical instrument.

Delving into weather trends, we determined how often the critical wind speeds would occur, and it is worth noting that we ruled out the seagulls (who stop squawking at night unlike our mystery sound).

We utilised prior research and wind tunnel data to confirm our suspicions, the brise soleil’s design created the perfect conditions for some architectural jazz but not all blades were responsible—only those exposed to perpendicular airflow.

Armed with insight, we crafted seven innovative remediation options. The preferred solution was a custom rubber extrusion to subtly thicken the lower edge of the brise soleil and disrupt the airflow responsible for the tone.

The extrusion was expertly fitted to the lower edge of the brise soleil blades by local steeplejacks quieting the building without compromising its elegant design or requiring costly scaffolding.

The final result: residents now enjoy peace and quiet, the building’s bold look remains intact, and local authorities are satisfied.

This project won us the top prize at the Association of Noise Consultants annual awards 2025. These awards demonstrate the unique skills of UK based acoustic consultants in addressing challenges, championing innovation and originality and showcasing the significance of a profession which blends art and science to transformational effect.