Cost saving of 70% acheived for acoustic treatment during conversion of a Listed Barn to Prestigious Offices

When Penna, Sanders & Sidney relocated to a prestigious office they found that several rooms were unsuitable for confidential discussions because speech in any one room could clearly be heard in adjacent rooms.

This problem was particularly severe between three ground floor rooms, intended for individual career counseling and a mezzanine level room directly above, proposed for group work.

In order to overcome the problem a quotation had been obtained for the installation of a false ceiling to the three ground floor rooms. This work would cost in excess of £7,000 and prevent any use of the rooms whilst the work was in progress. A further complication was that the already restricted ceiling height of 2100mm would be reduced to approximately 2080mm.

Fortunately, Acoustical Control Engineers was asked to review the proposal before a decision was made whether or not to proceed with the work as proposed. A cursory inspection releaved that the proposed treatment did not address the main problem with the existing construction and was not the most appropriate way to acheive a satisfactory level of performance.

This showed that noise breaking through the existing floor/ceiling was not the major problem and noise breaking through the gaps along the ceiling/wall interface was far more significant.

Five different sound transmission paths were identified. In approximate order of significance these were: gaps at the ceiling/wall interface; airborne sound breaking through the ceiling; flanking via the cavity behind the internal wall cladding; flanking via the gaps behind the beams; impact/movement sound. Even very small gaps dramatically reduce the acoustic performance of a partition and this degredation is most significant for higher performance system.