Redhill Library

Background 

Surrey County Council commissioned the full refurbishment of Redhill Library, a multi-storey public facility, to enhance its usability with flexible meeting spaces and improved public amenities.  

The project, led by Neilcott Construction Ltd, involved architectural and mechanical upgrades, including new partitions, finishes, and mechanical-electrical-plumbing (MEP) systems such as roof-mounted VRF units and an air-handling unit. 

Anderson Acoustics was appointed to provide comprehensive acoustic consultancy services, ensuring the design met both planning conditions and the Employer’s Requirements (ERs) for internal sound insulation, ambient noise levels, and building services noise control. 

What We Did 

Stage 4 Acoustic Design Review 

The Stage 4 design was assessed against the ERs established in the Stage 3 report by Atkins. Key areas of focus included: 

• Internal sound insulation performance of new and retained partitions;
• Impact sound insulation, particularly where vinyl flooring was proposed;  
• Acoustic treatment of ceilings;
• Junction detailing and control of flanking transmission;
• Reverberation times  

Mitigation measures were proposed where risks were identified, such as: 

• Upgrading vinyl flooring with resilient backing to meet impact sound criteria;
• Installing an independent wall lining to the plant room wall to ensure sufficient sound insulation performance to adjacent spaces;
• Recommending a mass backed ceiling tile to control flanking between offices where the partition could not be built to full height

Noise Impact Assessment 

A detailed assessment was conducted to evaluate the noise emissions from proposed plant equipment, including: 

• Air Handling Units (AHUs); 
• External VRV condensers 

Building Services Noise and Vibration Control 

We reviewed and advised on:- 

• Mechanical ventilation and heating/cooling systems;  
• Crosstalk attenuator performance;  
• Acoustic lagging of ductwork runs

Reverberation and Acoustic Finishes 

Ceiling and wall finishes were reviewed to ensure compliance with reverberation time targets. While ceiling systems aligned with Stage 3 recommendations, additional Class A wall absorbers were proposed for key rooms such as: 

• Flexible Meeting Room; 
• Partnership Office; 
• Work Room  

Commissioning Testing 

Commissioning testing of the plant systems was conducted to verify that the installed mechanical equipment (including roof-mounted VRF units and an air-handling unit) complied with the noise criteria established in previous design and planning documents.

The measured noise levels at all accessible monitoring positions were at or below both the predicted and target criteria with no further mitigation measures required.

Conclusion 

The acoustic design for Redhill Library successfully met all planning and performance criteria. Through detailed modelling and practical design recommendations, we ensured:- 

• Compliance with BS 4142 and planning conditions; 
• Effective control of internal and external noise; 
• Enhanced acoustic comfort for library users 

Project Progress 

Redhill Library reopened in October 2025. This refurbishment is part of the first phase of the Surrey Libraries transformation and modernisation programme facilitated by Surrey County Council’s Land and Property, Capital Projects teams.  

Anderson Acoustics are also supporting the Woking, Weybridge and Staines library refurbishment projects, working again with the team at Neilcott Construction.