Sound Testing: Lightweight construction pitfalls

The thermal insulating benefit and sustainability of lightweight aerated concrete blocks such as Aircrete, Celcon, Thermalite, Toplite and Durox makes them a popular building material in new builds, conversions and renovations. However, aerated concrete block construction does require additional acoustic consideration to avoid Approved Doc E pre-completion sound insulation test failures. What causes the problem? Lightweight aerated blocks are subject to flanking sound problems, particularly where this type of construction is mixed with separating timber floors and timber partitions between dwellings. This means that the sound vibration pathway may travel into and along a wall and break out of the wall into the room the other side of the partition resulting in insufficient sound insulation between dwellings. This problem can occur both in properties adjacent to each other and those built above or below each other. So shouldn’t I just improve the partition? No…. the mistake is often made of ‘beefing up’ the separating partition or floor by adding additional mass layers which often results in limited or no sound insulation improvement as the source of sound failure is due to flanking sound transmission rather than direct sound transmission through the separating element. This has a direct impact on wasted construction time, resources and increased material cost without solving the problem. Where can I get advice? Soundguard Acoustics has tested several constructions where this simple mistake could have been avoided by preliminary assessment of the constructions plans from an Acoustic Engineer. If you are considering this type of construction, particularly where timber floors and walls form a separating element, then we can review plans and undertake site visits for a nominal fee which could result in you avoiding the expensive corrections , development delay, further material costs, further build costs and repeated sound testing. Sounds good, what next? If you would like to know more about this and request a review of your development then contact us today on 0845 653 0233 or email

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