Acoustics case study

Downtown, Woden Street, Salford


New-build mixed use development of over 350 apartments with associated gym, cinema room and business centre on the banks of the River Irwell in Salford. Downtown is a collection of 6 interlinked blocks completed over two phases of construction, varying in height from 4 storeys up to 14. The development will provide a mixture of one, two and three-bedroom apartments close to Manchester city centre.


SRL were initially commissioned in 2014 to provide a noise impact assessment for the proposed development. We have since provided detailed design up to RIBA Stage 4, construction stage support, site inspections and a full schedule of commissioning testing to demonstrate compliance with Approved Document E. Phase 1 was successfully completed in 2019 and the second phase is on schedule for handover in the first quarter of 2020.

As with most other schemes, we identified areas of the design which could be value engineered which saved our client a significant sum of money. The two areas our client wanted us to focus on value engineering were:

  • Reducing the specification of the high performance glazing and mechanical ventilation across all facades due to the proximity Metrolink trams and heavy rail trains to the south
  • Avoiding the need for a resilient layer above the separating floor slab between apartments to comply with Approved Document E impact sound insulation criteria


Salford City Council’s planning authority set strict internal and external noise limits due to the proximity of a rail viaduct to the south of the development. SRL measured noise levels at key positions on the site and used detailed acoustic modelling techniques to show that only the most exposed facades at the south of the building required high performance glazing and mechanical ventilation to meet the internal noise limits. Facades below viaduct level, and those more sheltered from noise could meet internal noise limits using lower performance glazing and natural ventilation.

The locations of each glazing and ventilation was presented using colour coded facades, making our advice easier for other members of our design team to understand and saved our client a significant sum of money.

Our client also wanted to avoid using a resilient layer throughout the development, but needed to understand the risks involved and develop a solution to comply with the impact sound insulation requirements of Approved Document E.

Our proposed solution was to use a latex screed above the slab, which would be both cheaper and easier to install than a resilient layer. SRL provided impact sound insulation testing between two trial apartments which showed that the latex screed could sufficiently control impact noise above the slab. This also saved our client a significant sum of money and time.