Pre-Completion Sound Testing Requirements

What This Requirement Covers

Pre-completion testing (PCT) is one of two compliance routes under Approved Document E for demonstrating that separating walls and floors between dwellings meet the required sound insulation standards. The alternative route is the Robust Details scheme.

Key Requirements

When PCT Is Required

1. PCT is required for all separating walls and floors between new dwellings (purpose-built and conversions) unless the Robust Details route is used
2. Testing must be carried out before the Building Control completion certificate is issued
3. Testing is not required for walls and floors between dwellings and non-residential parts of the building

Testing Methodology

1. Airborne sound insulation: Tested to BS EN ISO 140-4 (or ISO 16283-1), producing a DnT,w + Ctr result
2. Impact sound insulation (floors only): Tested to BS EN ISO 140-7 (or ISO 16283-2), producing an L'nT,w result
3. Tests are carried out by an accredited testing body (UKAS accredited or registered with the Association of Noise Consultants)

Minimum Performance Standards

1. Separating walls (airborne): DnT,w + Ctr minimum 45 dB
2. Separating floors (airborne): DnT,w + Ctr minimum 45 dB
3. Separating floors (impact): L'nT,w maximum 62 dB

Sampling

1. Not every separating element needs to be tested; a representative sample may be agreed with Building Control:

- For a development with multiple identical constructions, a sample of separating elements may be tested - If any test fails, the sampling rate must increase (and potentially all elements of that type must be tested) - Building Control determines the sampling requirements based on the development size and construction type

What Happens If a Test Fails

1. If a separating element fails the PCT, the developer must carry out remedial work and retest
2. Common remedial measures include: adding mass (extra layers of plasterboard), sealing gaps, improving flanking construction, and adding resilient layers to floors
3. Building Control will not issue the completion certificate until satisfactory test results are provided

Practical Compliance Tips

1. Commission the sound testing early enough to allow for remedial work if needed; testing should be done after second-fix plastering but before occupation
2. Ensure the separating wall or floor construction matches the design specification; deviations (missing insulation, incomplete mortar joints, missing resilient bars) are the most common causes of failure
3. Seal all gaps and penetrations in separating elements with acoustic sealant
4. Do not install hard floor coverings (tile, laminate) on separating floors without a resilient layer; they will fail impact sound tests
5. Keep electrical sockets and service boxes on separating walls to an absolute minimum; each one weakens the sound insulation
6. Ensure the test rooms are in a suitable condition for testing (all openings sealed, no temporary heating or ventilation running)
7. Retain all sound test certificates for the building file and Building Control