Sound Insulation Part E Testing for New Builds and Conversions

Building Regulations Part E sets minimum sound insulation between flats, between rooms in residential, and between flats and common parts. Pre-completion testing has been mandatory for over a decade — and failures still happen on roughly 1 in 10 schemes.

The targets

Airborne sound between separating walls/floors of flats

• DnT,w + Ctr ≥ 45 dB (new build flats)
• DnT,w + Ctr ≥ 43 dB (conversions)

Impact sound on separating floors

• L'nT,w ≤ 62 dB (new build)
• L'nT,w ≤ 64 dB (conversions)

Internal walls and floors

• Rw ≥ 40 dB between rooms in single dwelling

Construction strategies

Walls

• Twin leaf masonry with cavity
• Steel/timber framing with twin plasterboard each side and acoustic infill
• Concrete blockwork with internal lining on resilient mounting

Floors

• Concrete slab + screed + resilient layer + floor finish
• Timber joist + resilient layer + plasterboard ceiling + insulation infill
• Engineered systems with floating floor

Testing

Mandatory for new flats, houses, and conversions. SANAS-accredited tester required.

• Test 1 in 10 of similar party walls/floors
• Airborne and impact tests separately
• Pass required before sign-off and occupation

Common failure modes

• Flanking transmission (sound around the separating element)
• Missed cavity barriers
• Penetrations not sealed acoustically
• Floor finishes installed without resilient layer
• Wrong plasterboard thickness or density

Robust Standard Details

Alternative to testing: use pre-approved construction details. Less common today as testing is now routine, but useful for some schemes.

Cost of remediation

Test failures after completion are expensive — typically R160,000–R500,000 per failed pair to remediate. Specifying conservatively and inspecting through construction is cheaper.

MCFAR coordinates acoustic specification with structural design.

Frequently Asked Questions