Background
Anderson Acoustics was commissioned by Morgan Sindall to provide acoustic design advice for the proposed Windmill School. The project involved the partial refurbishment, demolition, and new construction of a three-story building at 50 Moxon Street, Chipping Barnet, previously used as a warehouse and distribution center. The goal was to convert it into a special educational needs school for children with Autism (ASD) and co-existing conditions such as ADHD and social, emotional, and mental health (SEMH) needs.
The new facility will accommodate up to 90 primary and secondary students (ages 5 to 18) with significant barriers to learning associated with autism. The school will feature classrooms, specialist teaching areas (for subjects like science, cooking, art, design technology, and music), a dining area, a drama/dance studio for multisensory work, and a main hall for fitness activities and modified ball games.
It is the first publicly funded specialist school for autism in Barnet.
Our Approach
Acoustic Design Strategy
Listening is crucial in a school environment. Poor acoustics can hinder students’ ability to understand and retain information. For pupils with autism, who may be hypersensitive or hyposensitive to noise, acoustics are particularly important. Research shows that better acoustics can improve attention span, response times, and behaviour.
Our strategy ensured accessible listening conditions without compromising intelligibility for high-functioning students with ASD or triggering hypersensitive noise reactions. This approach also helps students adapt to different noise levels, promoting skill generalization in non-acoustically managed spaces.
Key Acoustic Solutions:
- Dining Room: Controlled noise build-up to create a calm atmosphere, with a kitchen layout designed to minimize noise transfer. This also allows for multipurpose use, such as music rehearsals.
- Ambient Noise Control: Achieved low mechanical system noise via NVHR units, maintaining good signal-to-noise ratios for students with special hearing and communication needs. We proposed improvements to meet BB93 new build standards without significant cost impact.
- Structure-Borne Sound: Implemented a floating roof floor to control sound transmission from play and sports activities.
- Reverberation Control: Enhanced Class A suspended ceilings with bass backing pads in technical teaching spaces and the drama room to meet enhanced reverberation time standards.
- Noise-Producing Equipment: Avoided noisy hand-dryers and fluorescent lighting to reduce noise.
- Airborne Sound Insulation: of separating & corridor walls – encasement of existing steel structure retained. Detailed assessment in order to minimize the extension of acoustic treatment.
- Vibration and Airborne Isolation: of a roof mounted air source heat pump ASHP located on the new lightweight roof – installation on a new concrete plinth supported on a secondary steel structure with specialist designer antivibration mounts.
Images source The Windmill School
Commissioning Testing
We conducted pre-completion testing to ensure compliance with Building Bulletin 93 (BB93) and noise-related planning conditions. The project aimed for a ‘Very Good’ rating under BREEAM UK’s sustainability assessment method for non-domestic refurbishment and fit-out, targeting all four credits in Hea05 (Health and Wellbeing – sound insulation, indoor ambient noise levels, reverberation times) and Pol 05 (Noise Pollution).
Our testing confirmed that all credits could be awarded with additional mitigation measures in place.
Project Progress
The project was completed in April 2024. The school is very pleased with the new building, and you can view more images on their website here.
An opening ceremony was held on 8th November 2024 with Morgan Sindall, School representatives and experts on autism.
