When existing buildings, such as offices and large singular houses are converted into dwellings, such as flats we often undertake sample sound testing to check the existing sound levels prior to the commencement of works, once we have established the sound test results we can then come up with a more cost effective and targeted design to comply with Part E of Building Regulations.
Historically, we have found that if the floor structure is a typical 200mm concrete slab the sample airborne results are often close to the requirements of Part E without undertaking any modifications to the existing slab; however, the impact results usually poor. This is because the airborne sound is broken down by the mass of the concrete slab, therefore sounds such as speech & TV etc. are minimised. Unfortunately, due to the lack of isolation and absorption within the concrete slab are usually poor as the impact noise can transfer straight through the slab and into the dwelling below. The resulting impact noise caused by people walking on the floor finishes above (especially if it is timber) can be very loud and may result in complaints from the new tenants. It may also fail the final precompletion sound test if no acoustic upgrades are made to the construction during the construction phase of the project.
Also, in our experience existing floors with a typical timber construction of 180mm timber joists and a single layer of 22mm floorboards to the top of the joists with a single layer of 12.5mm plasterboard to the underside of the joists usually achieves a sound test result of 26-30dB, which is well below the required 43dB. With this type of construction you are usually required to improve the mass, isolation and absorption within the floor construction.
To help reduce potential control noise issues APT Sound Testing can undertake an acoustic design review of the floors after sample sound testing to ensure both the airborne and impact sound tests pass Part E of Building Regulations. Using our extensive knowledge regarding the way different materials and construction methods can influence the results of sound testing we can offer easy to follow acoustic advice on the most awkward developments.
The 5 Main Design Considerations
To improve the chance of a successful sound test and reduce the chance of noise flanking you will need to ensure that you allow for the following five acoustic design considerations, when upgrading an existing floor they are:
We can advise on all types of acoustic design, whether it’s accomplished during initial construction or during a refurbishment/renovation project. We also undertake UKAS accredited sound testing providing a ‘one stop’ solution for all your acoustic requirements.
Alternately, If you would like more information on how to prepare for your sound testing please download our sound test checklist.