Floor Soundproofing

Acoustic Floor Underlay — Expert Soundproofing for UK Homes, Flats & Commercial Buildings

Noise transmission through floors is one of the most common acoustic challenges in UK residential and commercial buildings. Whether you're a homeowner dealing with footstep noise from upstairs neighbours, a developer specifying separating floors for a new build, or an architect designing a commercial space to meet Building Regulations Approved Document Part E, the right acoustic floor underlay makes the critical difference between compliance failure and a professionally quiet environment.

At Sound Deadening UK, our acoustic floor underlay range combines laboratory-tested performance data with practical installation engineering. Every product in this collection has been selected to deliver measurable noise reduction across both impact sound (footsteps, dropped objects) and airborne sound (voices, music, television) — with performance ratings clearly specified in decibels so you can specify with confidence.

Understanding the Two Types of Floor Noise

Impact Noise (Structure-Borne)

Impact noise is generated when a physical force — a footstep, a chair leg, a dropped object — strikes the floor surface. The energy propagates directly through the structural mass of the building, radiating as sound in the room below. Standard acoustic underlay addresses impact noise primarily through a resilient layer that absorbs and dissipates kinetic energy before it enters the structural slab or timber joist.

Impact noise performance is measured as ΔLw (Delta Lw) — the reduction in weighted normalised impact sound pressure level. A ΔLw of 20 dB is the typical minimum for meaningful acoustic improvement; our premium rubber underlays achieve ΔLw values up to 54 dB.

Airborne Noise (Transmitted Through Air)

Airborne noise — conversation, music, television — travels through the air and excites the floor structure when it strikes it. Heavier, denser underlays provide greater mass, which resists airborne sound transmission more effectively. This is why mass-per-unit-area (kg/m²) is a key specification for high-performance acoustic mats.

Our Acoustic Floor Underlay Range

Recycled Rubber Acoustic Underlay (3mm–6mm)

Our recycled rubber acoustic underlay is manufactured from post-consumer tyre rubber, providing excellent acoustic and environmental credentials. The dense, granulated rubber structure delivers superior impact noise reduction compared to foam alternatives of equivalent thickness. Available in 3mm (ΔLw ≈ 20–28 dB) and 6mm (ΔLw up to 54 dB) grades.

• Suitable for concrete and timber subfloors
• Compatible with laminate, engineered wood, LVT and ceramic tile
• Density: 400–600 kg/m³
• Compressive strength: withstands heavy furniture without creep
• Part E compliant when specified correctly

Cork Acoustic Underlay (3mm–10mm)

Natural cork offers a unique combination of thermal insulation, acoustic performance and sustainability. Cork's cellular structure — millions of air-filled micro-cells per cubic centimetre — makes it inherently resilient and vibration-absorbing. Our cork acoustic underlay range is certified sustainably sourced and performs excellently as a thermal break beneath timber floors.

• Thermal conductivity: λ = 0.038–0.045 W/m·K
• Impact noise reduction: ΔLw 16–24 dB (thickness-dependent)
• Natural anti-microbial and anti-fungal properties
• Ideal for eco-build and BREEAM projects

Multi-Layer Composite Acoustic Mats

For maximum performance — particularly in separating floors between apartments, or in commercial environments with high acoustic requirements — our multi-layer acoustic mats combine rubber, foam and mass-loaded vinyl elements to address both impact and airborne noise simultaneously. These systems are routinely specified by acoustic consultants for Building Regulations Part E compliance in converted dwellings.

Building Regulations Part E — Acoustic Floor Requirements

New Build Residential (Separating Floors)

Conversions and Material Change of Use

Pre-completion acoustic testing by an accredited engineer is required unless Robust Details (pre-approved construction methods) are used. Penalties for non-compliance under the Building Safety Act 2022 can include unlimited fines.

Application Guides

Acoustic Underlay for Concrete Floors

Concrete subfloors transmit impact noise efficiently due to their rigidity and mass. A resilient decoupling layer — rubber or multi-layer composite — is essential. For Part E compliance in flats on concrete decks, a minimum ΔLw of 20–28 dB is typically required depending on the overall floor build-up specification.

Acoustic Underlay for Timber Joisted Floors

Timber floors require a combination of resilient underlay (to reduce impact) and mass addition (to block airborne). Our rubber underlay systems, when combined with acoustic mineral wool in the floor void, routinely achieve the DnT,w and L'nT,w standards required by Part E. Contact our technical team for project-specific specifications.

Acoustic Underlay for LVT (Luxury Vinyl Tile)

LVT is popular but acoustically problematic — its rigidity transmits impact noise efficiently, and many standard LVT underlays are too thin to provide meaningful isolation. Our 3mm rubber acoustic underlay is specifically recommended for LVT over concrete in apartment buildings, where impact noise complaints are common.

Commercial and Educational Applications

For schools, colleges and healthcare environments, BB93 (Acoustic Design of Schools) and BS 8233:2014 (Guidance on Sound Insulation in Buildings) provide additional requirements beyond Part E. Our acoustic floor systems can be specified to meet these enhanced standards — contact our commercial sales team for CPD sessions and project support.

Installation Best Practice

• Full coverage: Acoustic underlay must cover the entire floor area — gaps create sound bridges that drastically reduce performance
• Perimeter upstand: Turn underlay up the walls by 10mm to prevent flanking transmission through the perimeter junction
• Joint sealing: Use acoustic tape on all butt joints to prevent sound leakage between sheets
• Acclimatisation: Allow materials to acclimatise for 24 hours in the installation environment
• Penetration sealing: Seal all service penetrations through the floor with acoustic sealant

Related Collections

For a complete acoustic treatment strategy, explore our complementary ranges:

• Timber Floating Floors — complete floating floor systems
• Acoustic Ceiling Solutions — treat the structure above
• Acoustic Insulation — wall and cavity insulation
• Accessories & Installation — tools, tape and sealants

Frequently Asked Questions

How much impact noise can acoustic underlay reduce?

Performance depends on material and thickness. Our 3mm recycled rubber underlay achieves ΔLw 20–28 dB; our 6mm premium rubber achieves up to 54 dB impact reduction. For reference, a 10 dB reduction equates to a perceived halving of noise loudness. Always check the ΔLw specification rather than relying on marketing claims alone.

Is acoustic underlay required by Building Regulations Part E?

Part E sets minimum standards for separating floors in new builds and conversions, but does not prescribe specific products — only performance outcomes. A suitable acoustic underlay is typically a key component of achieving compliance. Your specific requirement depends on the subfloor type, floor finish and overall build-up. We can provide project-specific guidance on request.

What is the difference between rubber and cork acoustic underlay?

Rubber (especially recycled rubber) provides higher impact noise reduction per millimetre of thickness, making it the preferred choice for technical acoustic compliance. Cork offers excellent thermal insulation alongside moderate acoustic performance and is preferred in eco-build projects or where natural materials are specified. Cork-rubber blend underlays combine both benefits.

Can I use acoustic underlay under carpet?

Yes. Acoustic underlay can be installed beneath carpet with a standard carpet underlay on top. However, the combined effect should be calculated carefully — stacking thick underlays can create instability under carpet, particularly in commercial applications. Our 3mm rubber underlay is ideal as a base layer under carpet for added acoustic performance.

What ΔLw rating do I need to meet Part E?

There is no single ΔLw figure for Part E compliance — the requirement depends on the complete floor system performance (DnT,w and L'nT,w), not just the underlay in isolation. As a guide, a ΔLw of 20 dB minimum is a sensible starting point for concrete subfloors. For timber floors, higher-performing underlays combined with additional mass layers are typically required. We recommend commissioning a pre-completion acoustic test to confirm compliance.