Sound Insulation in London
London is a major city in the UK containing in excess of 5 million dwellings. In this overcrowded and often noisy environment, it is essential that robust acoustic design is incorporated into all new and refurbishment projects from the offset.

To help enforce good acoustic design principles pre-completion sound testing was introduced in July 2003, this resulted in all new build properties and conversions that were built after this date are required 10% of each party wall/floor construction type to be tested.

Sound insulation testing is carried out between pairs of rooms separated by party walls or floors. The two ‘habitable’ areas that usually require sound testing are living rooms and bedrooms, although other rooms can be tested if this is not possible, i.e. kitchen to the bedroom.

APT Sound Testing undertakes UKAS accredited Part E sound testing throughout London and the South East. We have extensive knowledge regarding the way different materials and construction methods can influence the results of a sound test, so we can always offer robust and cost-effective acoustic design advice to ensure your compliance with Part E of Regulations. Our usual road map for design advice is:

1. Site Visits & Precompletion Testing
We offer Acoustic Site Survey Visits to let us view the existing site construction. This allows us to check for potential problem areas such as lightweight blocks that haven’t been used in the existing construction. It also lets us check that the installation teams are installing the acoustic materials as per the manufacturer’s guidelines, thus avoiding crucial onsite mistakes. In our experience, a sound test failure is often due to poor workmanship rather than the actual design. The site survey visits negate the risk of sound test failure.

We also undertake sample sound testing of the existing construction. This offers an accurate overview of the acoustic performance of the existing partitions which enables us to offer an acoustic design that correlates with the existing construction.

2. Acoustic Design Considerations
a.            Avoid using lightweight blocks in the inner envelope construction as sound will travel along light block-work both vertically and horizontally from dwelling to dwelling.

b.            The use of resilient suspended ceilings will help improve the performance of the floor partition.

c.             Use a high quality resilient acoustic membrane on top of the floor to improve the impact performance of a floor.

d.            Ensure all penetrations are fully sealed where they terminate through floors and they are adequately boxed with acoustic quilt and two layers of plasterboard.

Defect Diagnosis & Remedial Advice
With over 30 years’ experience in building acoustics, we are able to diagnose the reasons for the sound test failure and recommend a cost-effective solution. Often, the reasons for the partition failure are obvious to the test engineer in which case the advice will be minimal, and subsequently the cost for acoustic design advice will be minimal.

Sometimes, there are more technical issues that require more detailed diagnosis and invasive investigation, such as large amounts of noise flanking due to serious design faults, e.g. the use of lightweight blocks in the construction of apartment development.

Whatever the problem we can usually find an acoustic solution that will satisfy Part E of Building Regulations.

If you have a project that needs acoustic design advice or needs sound insulation testing then please contact us via the APT Sound Testing Website or phone us directly on 01525 303 905 and we should be able to offer you an expedient acoustic solution to help you achieve practical completion.

Designing Buildings to Pass Sound Testing
From the very start of the design phase of a new building, it’s extremely important that careful consideration is given to the acoustic element of the building.

By getting us involved at the start of the design process we can undertake comprehensive acoustic design reviews and ongoing site surveys. We always advocate meeting with the design team at the earliest opportunity to go through all acoustic elements for the building’s design, taking into account the site constraints and the most cost-effective method of achieving Part E of Building Regulations. We try to forward any possible ‘onsite’ construction problems and difficulties in achieving successful acoustic construction and subsequently the sound testing for Part E.

Once we have completed the acoustic design review our services don’t finish there. We provide the site team with ongoing design support and site visits. You will have direct contact with the allocated acoustician from the start of the process through to the successful completion of the project.

Acoustic Design & Onsite Construction
Once the first phase of the building is completed, we can undertake sample sound testing to ensure the acoustic design and onsite construction methods are sufficient to pass Part E sound testing.

When it comes to refurbishment projects i.e. houses converted into flats and/or office blocks into flats we can undertake a sample test of the existing wall and floor construction. Once we have established the sound levels for the existing construction we can then look at the extent of the acoustic upgrades to attain Part E Complaisance. This is much more effective than just forwarding an acoustic design that may be too excessive and expensive when the existing construction is already ‘acoustically’ robust and therefore only needs to improve by a few dB.

One problem we often encounter (without our design input) is that the building marginally fails during the sound test. The potential problem that is often overlooked is that many types of acoustic design/materials have attained an acoustic rating within a laboratory. It is very difficult and extremely unlikely that the sound levels achieved on a construction site will be as good as in the confines of a stringent laboratory environment.

When the construction assembly is tested in the lab, it is also certified and an exact description of the materials and the installation techniques are described in detail and followed to the letter, obviously, this should be replicated on your site as closely as possible, however, this seldom happens. This is one of the reasons why a 5dB point difference is allowed between the construction design on paper and the actual on-site construction performance.

When you consider that sound doubles every 10dB, then 5dB can make a huge difference to the overall performance of the dividing partition under test. If consideration is not allowed during the design process then there will be a greater chance of a sound test failure on your project. 

Another potentially problematic area of sound transference and potential sound test failures is down to flanking sound. Noise flanking is when travels along a continuous path due to insufficient isolation/break within the building wall & floor elements. One of the most common flanking paths is along with the inner leaf of an external cavity wall. This may be due to lightweight block construction resulting insufficient mass to prevent noise transference.  

Unwanted noise travelling along flanking paths makes the building structure vibrate and this causes the sound to radiate into your room. One solution is to build another wall or ceiling in front of the original, but not connected to it (often called an independent wall or ceiling). APT can help to locate the flanking sound and propose a cost-effective design that will pass the sound testing and satisfy Part E of Building Regulations.

For the smaller projects, we undertake a more simplified acoustic design service consisting of a review of the design drawings, such as to floor plans and sections. This usually takes place straight after planning has been approved as increased cost savings can be realised at the earliest stage. We can also undertake sample sound testing if the client is not sure of the existing onsite construction.

We can then evaluate the building design to ensure that it the walls and floors are capable of meeting the acoustic requirements of Approved Document E.

Some of the main areas we consider are:

•             There are no potential flanking points, where isolated partitions are wrongly mechanically fixed together to cause noise bridging or the wrong materials have been specified such as lightweight blocks etc.

•             The acoustic treatments for Soil Pipes, Stair Cases Steel Beams, etc. to ensure they are acoustically fit for purpose, as these are some of the many areas that get missed.

•             Acoustic floor treatments are compatible with the proposed floor finishes i.e. Carpets, Laminates, Floor Tiles and under-floor heating systems.

•             The Lighting specification to, ensure they are acoustically compliant to the overall design i.e. down lighter design, etc.

If you would like more information in regards to sound testing please follow our blog at: http://soundtestinguk.blogspot.co.uk/, or contact us at: info@aptsoundtesting.co.uk or visit the APT Sound Testing website.