Acoustic Underlay Comparison 2025: Cork, Rubber, or SilentMat for Your Project?

Choosing the Right Acoustic Underlay for Your Flooring Project

Selecting the right acoustic underlay can make the difference between a floor that meets Building Regulations and one that fails acoustic testing. With multiple options available—cork and rubber underlays, professional acoustic mats, and specialized systems—how do you choose the right solution for your project?

This comprehensive comparison guide explains the differences between acoustic underlay types, their performance characteristics, ideal applications, and helps you select the right product for your specific flooring project.

Understanding Acoustic Underlay Types

1. Cork & Rubber Acoustic Underlay (3mm & 4.5mm)

Cork & Rubber Acoustic Underlay combines waste rubber, cork, and polymer binder to create a resilient, eco-friendly matting suitable for residential and commercial applications.

Key Features:

• Thickness: 3mm or 4.5mm
• Material: Recycled rubber + cork granulate
• Impact sound reduction: 18 dB (3mm) / 21 dB (4.5mm)
• Fully recycled and environmentally friendly
• Document E compliant
• Compatible with underfloor heating

Best For: Residential flooring, vinyl, laminate, engineered wood, refurbishment projects, and applications where eco-credentials matter.

2. FFR Acoustic Rubber Underlay Roll

SilentCloud FFR Acoustic Rubber Underlay is engineered from recycled rubber granulate with cold cure PuR elastomer bonding, delivering superior sound insulation for timber and concrete floors.

Key Features:

• Thickness: 3mm - 12mm (multiple options)
• Material: Rubber granulate + PuR elastomer
• Impact sound reduction: Up to 21 dB (5mm)
• Density: 730 kg/m³
• Continually elastic (no sagging like foam)
• Document E compliant

Best For: Commercial projects, high-traffic areas, timber floors, concrete floors, hard surfacing, and applications requiring long-term durability.

3. SilentMat 15mm Professional Acoustic Mat

SilentMat 15mm is a professional-grade floating-floor acoustic system engineered to deliver higher impact and airborne sound reduction than traditional mass-dominant floor mats.

Key Features:

• Thickness: 15mm
• Construction: Engineered multi-layer composite (mass + tuned resilience)
• Impact sound reduction: 28-36 dB (depending on system)
• Airborne sound improvement: 15-22 dB
• True floating-floor decoupling
• Stable under residential loads

Best For: Separating floors in apartments, Part E compliance projects, timber joist floors, developments requiring measured acoustic performance, and professional installations.

Performance Comparison Table

When to Use Each Type

Choose Cork & Rubber Underlay If:

• ✓ You're installing vinyl, laminate, or engineered wood flooring
• ✓ It's a residential project (not separating floors)
• ✓ You need eco-friendly, recycled materials
• ✓ Budget is a primary consideration
• ✓ Floor height is limited (3-4.5mm build-up)
• ✓ You have underfloor heating

Choose FFR Rubber Underlay If:

• ✓ It's a commercial or high-traffic application
• ✓ You need long-term durability and elasticity
• ✓ You're working on timber or concrete floors
• ✓ You want superior resilience (no foam sagging)
• ✓ The project requires Document E compliance
• ✓ You need various thickness options (3-12mm)

Choose SilentMat 15mm If:

• ✓ You're soundproofing separating floors in apartments/flats
• ✓ The project must meet Part E Building Regulations
• ✓ You need maximum impact AND airborne sound reduction
• ✓ It's a timber joist floor requiring professional performance
• ✓ You want engineered performance, not just mass
• ✓ Pre-completion acoustic testing is required

Installation Considerations

Cork & Rubber Underlay Installation

• Roll out underlay perpendicular to flooring direction
• Butt joints tightly (no overlapping)
• Tape seams with appropriate tape
• Install flooring immediately over underlay
• Compatible with click-lock and glue-down flooring

FFR Rubber Underlay Installation

• Ensure subfloor is clean, dry, and level
• Roll out underlay with minimal gaps
• Tape seams to prevent movement
• Can be used under hard surfacing or carpet
• Suitable for both timber and concrete subfloors

SilentMat 15mm Installation

• Install as part of floating-floor system
• May require MDF/chipboard load-spreading layer (check flooring manufacturer requirements)
• Maintain perimeter isolation (10-15mm gap)
• Seal perimeters with acoustic sealant
• No mechanical fixings through isolation layer
• Fill joist cavities with mineral wool (timber floors)

Cost vs Performance Analysis

Budget-Friendly Option

Cork & Rubber 3mm: Most economical choice for residential projects where moderate acoustic improvement is acceptable. Ideal for refurbishment and DIY installations.

Mid-Range Performance

Cork & Rubber 4.5mm or FFR 5mm: Better acoustic performance with good durability. Suitable for most residential applications and light commercial use.

Professional-Grade Solution

SilentMat 15mm: Premium pricing but delivers measured, regulation-compliant performance. Essential for separating floors and projects requiring acoustic testing.

Common Mistakes to Avoid

1. Using Residential Underlay for Separating Floors

Mistake: Installing 3-5mm cork/rubber underlay on separating floors between dwellings.

Result: Fails to meet Part E requirements; costly remediation required.

Solution: Use SilentMat 15mm or engineered overlay systems for separating floors.

2. Overlapping Underlay Seams

Mistake: Overlapping underlay rolls at seams.

Result: Creates uneven floor surface, visible ridges under flooring.

Solution: Butt joints tightly and tape seams.

3. Skipping Perimeter Isolation

Mistake: Installing floating floors without perimeter gaps.

Result: Acoustic flanking through rigid connections to walls.

Solution: Maintain 10-15mm expansion gap and seal with acoustic sealant.

Building Regulations Compliance

Document E Requirements

For separating floors in residential buildings:

• Impact sound insulation (L'nT,w): Maximum 62 dB
• Airborne sound insulation (DnT,w): Minimum 45 dB

Which Products Comply:

• Cork & Rubber 3-4.5mm: Suitable for non-separating floors only
• FFR Rubber: Document E compliant when used in appropriate systems
• SilentMat 15mm: Specifically designed for Part E separating floor compliance

Underfloor Heating Compatibility

All three underlay types are compatible with underfloor heating, but thermal conductivity varies:

• Cork & Rubber: Good thermal conductivity; minimal impact on heating efficiency
• FFR Rubber: Excellent thermal properties; suitable for UFH systems
• SilentMat 15mm: Verify compatibility with specific UFH system before installation

Important: Always check with your underfloor heating manufacturer to ensure underlay thickness and thermal resistance are within system specifications.

Environmental Considerations

Sustainability Credentials

• Cork & Rubber: Fully recycled materials; eco-friendly choice
• FFR Rubber: Made from recycled rubber granulate; sustainable option
• SilentMat 15mm: Engineered for performance; check manufacturer for recycled content

All SilentCloud underlays contribute to sustainable building practices and can support LEED® points in commercial projects.

Quick Selection Flowchart

Is it a separating floor between dwellings?

• YES → Use SilentMat 15mm
• NO → Continue below

Is it a commercial or high-traffic application?

• YES → Use FFR Rubber Underlay
• NO → Continue below

What's your floor height restriction?

• Very limited (3mm) → Use Cork & Rubber 3mm
• Moderate (4-5mm) → Use Cork & Rubber 4.5mm

Get Expert Underlay Selection Advice

Still not sure which acoustic underlay is right for your project? Our technical team provides:

• Application-specific product recommendations
• Performance calculations for your floor construction
• Building Regulations compliance verification
• Installation guidance and best practices
• Quantity calculations and project pricing

Contact us today for personalized acoustic underlay advice.

Conclusion: Match Your Underlay to Your Application

The right acoustic underlay depends on your specific application:

• Residential floors (non-separating): Cork & Rubber 3mm or 4.5mm
• Commercial/high-traffic: FFR Rubber Underlay
• Separating floors/Part E compliance: SilentMat 15mm

By selecting the appropriate underlay for your floor type and performance requirements, you'll achieve reliable acoustic performance, regulatory compliance, and long-term durability.

Browse our complete range of acoustic underlays and flooring solutions to find the perfect match for your project.