Pre-completion sound insulation testing catches more developments out than it should – not because the standards are complicated, but because it tends to be the last test scheduled and the first one forgotten. Get acoustic testing wrong, or leave it too late in the build programme, and Building Control simply won’t sign off the development. With flats, conversions, hotels and care homes all falling under the same requirement, it’s worth understanding exactly what Part E asks for before it becomes a completion-week problem.
In this blog you’ll learn:
- What Part E actually requires, and which building types it applies to
- The sound insulation standards your development needs to hit
- When on-site testing needs to happen – and why timing catches developers out
- How acoustic testing fits alongside the other pre-completion compliance testing your development also needs
What is Part E, and Which Buildings Does it Apply To?
Part E of the Building Regulations governs sound insulation between dwellings in England and Wales, with equivalent requirements set out in Section 5 of the Building Standards in Scotland and Technical Booklet G in Northern Ireland. It’s a legal requirement for newly built dwellings, conversions and residential units such as flats, hotels and care homes – anywhere a party wall or party floor separates one household or occupant from another.
Acoustic testing must be carried out by a suitably qualified, accredited acoustic consultant, and the results feed directly into the Building Control sign-off process. There’s no self-certification route here – if the test isn’t booked with an appropriately accredited consultant, Building Control won’t accept the result.
The Sound Insulation Standards You Need to Hit
The threshold depends on whether the work is a new build or a conversion:
- New build (walls and floors): airborne sound insulation must achieve a minimum of 45 dB DnT,w+Ctr (higher is better), and impact sound insulation must not exceed 62 dB L’nT,w (lower is better)
- Conversion or material change of use: airborne sound insulation must achieve a minimum of 43 dB DnT,w+Ctr, and impact sound insulation must not exceed 64 dB L’nT,w
Two distinct types of sound are measured: airborne sound (speech, TV, general household noise) transmitted through party walls and floors, and impact sound (footsteps, moving furniture) transmitted through party floors, measured using a calibrated tapping machine.
How Acoustic Testing Works, and Why Timing Matters
Standard regulations require one set of tests for every 10 units in a group or sub-group, with a standard test set generally covering two airborne wall tests, two airborne floor tests and two impact floor tests between habitable rooms.
Timing is where developments most often come unstuck. Testing has to happen pre-completion, once the building envelope is fully sealed – walls plastered, internal and external doors and windows fitted, power operational – but before soft floor coverings like carpet, laminate or underlay go down. Book it too early and the building isn’t ready to give an accurate result; leave it too late and a failed test means ripping up new flooring to fix a wall or floor build-up that should have been caught weeks earlier.
Who Can Carry Out the Acoustic Testing
Building Control only accepts results from a consultant accredited through UKAS or the Association of Noise Consultants (ANC) Registration Scheme. It’s a specific, separate accreditation from the testing BEE carries out directly, which is why we refer acoustic testing enquiries to Acoustic Consultants, our long-standing ANC-accredited partner – in the same reciprocal relationship that sees them refer their air tightness testing needs to us.
Part E is One Piece of New Build Compliance – Not the Whole Picture
Acoustic testing rarely arrives on its own. Most new build and conversion projects that need a Part E sound test are working through the same pre-completion crunch on several other fronts at once, and all of them carry the same risk: get the timing or the design wrong, and it’s Building Control sign-off that stalls.
- Part L – air tightness testing. Every new dwelling needs a measured air permeability result before it can be signed off, and a failed test means a retest, a schedule delay and added cost on every affected plot.
- Part F – ventilation testing and commissioning. Extract rates, background ventilation and purge ventilation all need to be measured and commissioned on completion, not assumed at design stage.
- Part O – overheating risk assessment. Increasingly relevant on developments with larger glazing areas or restricted night-time ventilation, and worth resolving at design stage rather than after a plot has already been built.
Our Expert Insight
Where acoustic testing genuinely differs from Part L, F and O is that it’s the one test on this list BEE doesn’t carry out directly – it’s specialist enough to sit with a dedicated ANC-accredited partner. Everything else on a typical new build compliance programme – air tightness, ventilation commissioning, overheating risk – we deliver in-house, usually across the same site visits, which is often what keeps a tight completion schedule intact when one test result comes back marginal.
What’s Next?
A development rarely needs just one of these tests in isolation – Part E, L, F and O compliance tend to land in the same few weeks of a build programme, and a delay on one can hold up the rest. If you’re coordinating a new build or conversion toward completion, it’s worth getting air tightness testing, ventilation testing and commissioning and overheating risk assessments booked in alongside your acoustic testing, not as an afterthought once a plot has already failed.
If you’re planning a new build or conversion and want to get your Part L, F and O testing in one place, our team can help you sequence it properly.