What Is the Best Acoustic Underlay for a Flat? (Expert Answer)

Written by our acoustic insulation specialist — 15+ years experience supplying soundproofing to UK homeowners, developers and contractors. About our experts.

Expert answer from our acoustic insulation specialist.

After advising hundreds of flat owners on this exact problem, our recommendation is clear: for most flats, our 6mm recycled rubber underlay at 74dB is the right starting point.

Why Flats Have a Noise Problem

Flats suffer from both impact noise (footsteps) and airborne noise (voices, TV) through the separating floor. Standard underlay does almost nothing — it is designed for comfort, not acoustic performance.

Part E Requirements for Flats

Building Regulations Approved Document E requires: new builds DnT,w ≥ 45dB / L'nT,w ≤ 62dB; conversions DnT,w ≥ 43dB / L'nT,w ≤ 64dB. A single underlay cannot achieve this alone — you need a system. But the right underlay is the foundation.

Our Recommendation

For most flats: 6mm acoustic rubber underlay (74dB). For compliance-critical projects: 12mm acoustic flooring system. Contact our team for a free recommendation.