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Part E · As Built Testing

Sound Insulation Testing
for Part E compliance.

UKAS-accredited airborne and impact sound testing for new build and conversion dwellings. Reports within 24 hours. Can be combined with air tightness testing on the same site visit.

24 hr
report turnaround
after test
Combined
with air tightness
on same visit

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Airborne and impact — understanding which tests apply to your project.

Part E requires different tests depending on the type of separating element and the building configuration. Most new build and conversion projects require both.

Test type 1
Airborne Sound Insulation

Airborne tests measure how much sound from speech, music, or television passes through a separating wall or floor from one dwelling into an adjacent one. A loudspeaker generates a known sound level in the source room; a precision microphone measures the level received in the adjacent room.

The result is expressed as DnTw + Ctr (dB) — the weighted standardised level difference, adjusted for low-frequency noise. Higher values mean better sound insulation.

Required for
  • Separating walls between adjoining dwellings
  • Separating floors between dwellings in apartments
  • Separating walls in terraced and semi-detached houses
  • All new build and material change-of-use conversions
Test type 2
Impact Sound Insulation

Impact tests measure how well a floor prevents footstep noise and other structure-borne impacts from being transmitted to the room below. A calibrated tapping machine drops a series of hammer blows onto the floor above; a precision microphone measures the resulting impact noise level in the receiving room beneath.

The result is expressed as LnTw (dB) — the weighted standardised impact sound pressure level. Lower values mean better impact sound insulation.

Required for
  • Separating floors between apartments only
  • Not required for separating walls
  • Not required for houses (no separating floor between dwellings)
  • No floor coverings (carpet, laminate) may be fitted before testing

The Part E performance values your build must achieve.

Airborne — New Build
Separating walls
≥ 45 dB
DnTw + Ctr — weighted standardised level difference
Airborne — New Build
Separating floors
≥ 45 dB
DnTw + Ctr — weighted standardised level difference
Impact — New Build
Separating floors
≤ 62 dB
LnTw — weighted standardised impact sound pressure level
Airborne — Conversion
Walls & floors
≥ 43 dB
DnTw + Ctr — slightly relaxed for existing structure conversions

What happens on the day of your sound test.

A typical sound test for a set of party walls and floors takes between two and four hours on site, depending on the number of separating elements to be assessed.

01
Site readiness check
We confirm the property meets the minimum preparation requirements before setting up equipment — all finishes complete, no floor coverings on separating floors, no background noise from construction.
02
Airborne wall tests
Loudspeaker generates a defined sound level in the source room. Precision microphone measures the received level in the adjoining room. Conducted on all separating party walls.
03
Floor tests (airborne & impact)
Airborne floor test measures sound passing through the separating floor. Impact test uses a calibrated tapping machine on the floor above and measures the resulting noise in the room below.
04
Report & certificate
Full test report with DnTw + Ctr and LnTw results issued within 24 hours. Pass certificates provided for Building Control. Failure reports include guidance on likely causes and remedial options.

How many tests does your development need?

Part E sets out minimum sampling requirements based on development size and construction type. For small developments with consistent construction, you won't need to test every separating element — but the minimum number must be tested to a prescribed pattern.

For a typical small residential development of fewer than ten similar units, a minimum set of tests normally includes two airborne wall tests, two airborne floor tests, and two impact floor tests. If any test fails, all remaining untested elements of the same type must be tested.

For larger developments, the required number of tests increases. We confirm the minimum requirement for your specific scheme before booking — and can advise on a testing programme that fits your completion schedule.

Typical test requirements by element

Separating walls (party walls) Between adjoining houses or apartments
Airborne
Separating floors — apartments Between vertically stacked dwellings
Airborne Impact
Separating floors — houses Floor between ground & first floor of same house
Not required
Conversion — walls & floors Material change of use to new dwellings
Airborne Impact
Rooms for residential purposes HMOs, student accommodation, care homes
Airborne

Getting your build ready — and avoiding a re-test.

Sound tests are sensitive to site conditions. Background noise from adjacent construction activity, incomplete finishes, or floor coverings that shouldn't yet be fitted are among the most common reasons for invalid results or failed tests — almost all of which are avoidable with the right preparation.

The most important rule for impact testing: no floor coverings on separating floors before the test. Carpet, laminate, or engineered flooring applied before the impact test will improve the measured result but invalidate it — because the test is assessing the structural floor, not the finished surface.

We send a full preparation checklist at the point of booking. If you are unsure whether your site is ready, call us before the test day rather than after — it saves time and avoids wasted visits.

Site readiness checklist

All windows and external doors fitted, glazed, and closed External openings must be complete and sealed during testing.
Walls, floors, and ceilings fully finished All plasterboard, plaster skims, floor screeds, and ceiling finishes must be complete.
No floor coverings on separating floors Carpet, laminate, and engineered flooring must not be fitted before impact testing.
Skirting boards and electrical fittings in place Skirting, sockets, light switches, and architraves influence acoustic performance and should be fitted.
No construction activity during testing Drilling, hammering, or other noisy work elsewhere in the building will invalidate results.
Access to both sides of every separating element We need access to both rooms either side of each party wall or floor being tested.
240v mains power supply available Our testing equipment requires a working mains supply in the rooms being tested.

Flanking transmission — the hidden cause of most failures.

A well-designed and correctly specified separating wall or floor can still fail a sound test if flanking transmission is not controlled. Flanking occurs when sound travels via indirect routes — through the floor screed, ceiling void, wall ties, or connected structural elements — rather than directly through the separating element itself.

It is one of the most common causes of unexpected test failures, particularly in masonry construction where continuous floor screeds, wall plates, and ring beams create efficient flanking paths that no amount of acoustic insulation in the party wall will address.

The solution is almost always a design-stage decision — flanking routes need to be broken by physical discontinuities, resilient fixings, or correctly specified acoustic barriers at junctions. Retrofitting these after construction is difficult and expensive.

Detail junctions carefully at design stage
Wall-to-floor, wall-to-ceiling, and wall-to-wall junctions are the primary flanking paths. These must be robustly detailed before construction begins — not resolved as an afterthought.
Lap acoustic barriers correctly
Acoustic membranes and barriers must be lapped and sealed at all edges and junctions. Gaps, tears, or incorrectly terminated edges significantly reduce effectiveness.
Use resilient channels and independent ceilings
Resilient channels break the direct structural connection between ceiling and floor structure, interrupting one of the most common flanking paths in multi-storey residential buildings.
Supervise workmanship at critical stages
Acoustic performance depends on construction quality. Regular inspection at the stages where acoustic details are installed — before they are concealed — prevents costly failures at testing.

Local Part E accredited testers across the Midlands and South West.

We coordinate sound insulation testing around your completion programme, often on the same site visit as air tightness testing to reduce costs and disruption.

Birmingham & West Midlands
Sound insulation testing for new build flats, conversions, and attached dwellings across Birmingham, Solihull, Coventry, Wolverhampton, and the wider West Midlands. Airborne and impact testing to Part E standards.
Bristol & South West
Part E compliance testing across Bristol, Bath, South Gloucestershire, and the surrounding South West. We test separating walls and floors in flats, terraces, and semi-detached homes.
Worcestershire
Based in Worcester — sound testing across Malvern, Droitwich, Evesham, Bromsgrove, and Redditch. Our home county with the fastest response times and deepest local relationships.
Gloucestershire
Sound insulation testing for conversions and new builds across Cheltenham, Gloucester, Stroud, Tewkesbury, and the Cotswolds. Certificates accepted by all local Building Control authorities.
Oxfordshire
Part E sound testing for attached and converted dwellings across Oxford, Banbury, Bicester, Witney, and the wider Oxfordshire area. Often combined with air tightness testing on the same visit.
Wider England & Wales
Our sound insulation test certificates are valid across the whole of England and Wales. We regularly test on projects outside our core regions — contact us wherever your development is.

Looking for sound insulation testing near you? Whether you have a conversion in Cheltenham, an apartment block in Birmingham, or a terrace development in Bristol — we deliver compliant Part E results with pre-test guidance to help you pass first time. Call 01386 365145 or email us to book.

Common questions about sound insulation testing.

It depends on your development type. All separating walls require airborne testing. Separating floors between apartments require both airborne and impact tests. Houses do not have separating floors between dwellings, so only airborne wall tests are required for typical terraced or semi-detached houses.

If you're unsure which tests apply to your project, contact us before booking and we'll confirm based on your building type and configuration.

Approved Document E specifically calls out that testing should be carried out by a UKAS-accredited body or equivalent. Many local Building Control authorities and NHBC warranty inspectors require UKAS-accredited results before accepting compliance.

Using a non-accredited tester risks having your results rejected and needing to retest, causing delays and additional cost. Our UKAS accreditation means your certificates will be accepted by all Building Control bodies in England and Wales.

If a test fails, our report will include the measured result, the shortfall against the required standard, and guidance on the most likely causes. Common reasons include flanking transmission, unsealed gaps around service penetrations, incomplete skimming of party walls, or missing/incorrectly installed acoustic membranes.

In most cases we can advise on targeted remedial measures that don't require demolition of the separating element. Once remediation is complete, a re-test is arranged. We try to accommodate re-tests quickly to minimise delays to your completion programme.

Yes — this is something we actively encourage for developments that require both tests. Combining air tightness and sound insulation testing on the same site visit reduces programme disruption, cuts travel costs, and means a single report covers both compliance requirements.

If you are also working with us on SAP calculations, we can align the testing visit with your as-built assessment timeline to make the completion process as efficient as possible.

A standard set of tests for a typical pair of semi-detached or terraced houses — two airborne wall tests — usually takes around two hours on site. For an apartment block requiring airborne wall tests, airborne floor tests, and impact tests, allow a full working day depending on the number of units.

We work efficiently and aim to minimise disruption to your programme. For larger developments we agree a testing schedule in advance that aligns with your completion phasing.

Yes. Part E makes a distinction between new build and material change of use (conversion) projects. The minimum performance standard for conversions is slightly relaxed — 43 dB DnTw + Ctr for airborne tests rather than 45 dB — to account for the constraints of working within an existing structure.

The test methodology and preparation requirements are the same. However, older buildings can present additional flanking risks from continuous structural elements, so it's worth discussing the specific construction with us before the test day.

Same-visit with air tightness

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