Tom Gregory, head of Chiltern Dynamicsexternallink Energy Services Department, answers the most frequently asked questions about sound insulation testing as required under Approved Document E.

Sound insulation

E1) Which projects need to be tested under Approved Document E (ADE)?
Flats, houses and rooms for residential purposes (e.g. care homes, student accommodation, hotels) either new build or formed by material change of use.

Builders can either test to the regime set out in ADE, or pay to use Robust Details, a set of specific design details for walls and floors that have been previously tested. Testing provides more flexibility by allowing out of the ordinary designs. NB: Rooms in other buildings may also need to be tested for specific or client requirements e.g. classrooms (BB93) or consulting rooms in hospitals/surgeries.

E2) What do buildings need to achieve?
Party walls and floors need to achieve an airborne sound insulation of greater than 45dB (43dB for change of use). Party floors need to achieve an impact sound insulation of less than 62dB (64dB for change of use).

E3) How many units need to be tested under ADE?
It states that one set of tests is required for every 10 units in a group or sub-group, defined as a significant change in design or use and broken down in detail in ADE.

  • For new build houses – one set of two tests on the walls
  • For new build flats - one set of six tests on separating walls & floors (two airborne wall tests, two airborne floor tests and two impact floor tests)
  • Rooms for residential purposes (student accommodation, hotel rooms, care homes etc) – one set of three tests: one airborne wall test, one airborne floor test and one impact floor test
  • For change of use (e.g. conversion of houses to flats or non-dwellings to dwellings) all of the above rules also apply.

E4) How are units selected for test?
Typically this is left to the discretion of the test engineer. However the local authority building control officer, warranty provider or other concerned parties may wish to test in specific areas. Tests are always conducted between pairs of rooms.

E5) Who is competent to conduct the testing under ADE?
The testing body should be UKAS-accredited, or a member of the Association of Noise Consultants (ANC).

E6) What are the common problem areas?
Many aspects of the build can affect the acoustic performance of the separating walls or floors. One of the single largest factors influencing performance is, predictably, workmanship. Sealing of air paths, clearing of cavities and good detailing are all key aspects in maximising on site performance. Generally, good workmanship for acoustic performance also leads to a better air leakage performance and we strongly advocate this to clients. Sound testing needs to be taken into account very early in the construction stage, to make sure a correct combination of building materials is used to achieve the performances required.

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