Office to apartments conversion acoustic design, Douglas, Isle of Man

When the owner of an office building on the Isle of Man took the decision to redevelop the property into four apartments, he partnered with chartered architect Andrew Bentley to arrive at a design.

The building had previously been converted from a bar to offices in the 1990s, but the approach adopted to the soundproofing as part of this conversion project would need to be fully assessed and tested for compliance with today’s domestic dwelling standards.

STEPPING UP TO HIGHER ACOUSTIC STANDARDS

Under the building regulations covering the Isle of Man, which are consistent with Approved Document E in England & Wales, the separating floors needed to achieve an airborne sound transmission level greater or equal to 43db and, for impact sound transmission, no higher than 64db.

Following a comprehensive consultation period by Hush Acoustics soundproofing experts, it was apparent that the existing acoustic flooring design fitted during the original conversion was inadequate. This meant a complete redesign of the floors was required to bring them up to an acceptable residential standard.

A SOLUTION THAT EXCEEDED EXPECTATIONS

The solution came with the Hush MF Ceiling System. This creates a suspended ceiling, separated from the existing structure using the Hush Acoustic Hangers, allowing for Hush-Slab 100 sound absorber slabs to be fitted into the void created. Two layers of 15mm Soundbloc plasterboard were then installed onto the suspended ceiling’s metal frame.

Key to the success of the new acoustic system was the quality of the installation, which the Hush Acoustics team – as with all projects – offered guidance on to the installation contractor. This was important from a fire safety perspective too, with a fire specialist also engaged to ensure all gaps, junction details and products were installed and sealed correctly.

‘BEST EVER’ ACOUSTIC RESULTS

As a result of this new acoustic flooring, the flats benefit from soundproofing levels not normally seen in conversion projects of this kind. The airborne sound insulation levels for the floors tested in various rooms ranged from 50db to 67db (minimum level to pass test is 43db) and for impact sound it was between 38db and 50db (must be below 64db).

Project architect Andrew Bentley commented:

“The test results were so good that the acoustician who carried out the testing of the completed installation said it was the best results he had ever seen. In the lounge of one of the flats, there was virtually no background noise detected despite sound of 107db being generated in the lounge of the flat directly above – that’s a noise level almost as loud as you would experience at a rock concert.”