Soundproofing Floors Between Flats: Complete Guide to Impact Noise Reduction

Why Floor Soundproofing Is Critical in Multi-Storey Buildings

Impact noise from floors above is the most common noise complaint in flats and apartments. Footsteps, dropped objects, furniture movement, and children playing generate vibrations that travel directly through the floor structure and radiate as noise in the flat below.

Effective floor soundproofing is essential for:

• Meeting Building Regulations Part E impact sound insulation requirements (L'nT,w ≤ 62 dB)
• Preventing tenant complaints and disputes between neighbours
• Maintaining property value and rental appeal
• Creating peaceful living environments in multi-occupancy buildings
• Avoiding enforcement action and costly remedial work

Understanding Impact Sound Transmission

Impact noise differs fundamentally from airborne noise. When someone walks across a floor, the impact creates vibrations that travel through the structural floor slab and radiate as sound in the room below. Standard carpet or underlay provides minimal reduction—professional acoustic treatment is required.

Part E Requirements for Floors

Building Regulations Approved Document E specifies maximum impact sound levels:

• Maximum L'nT,w ≤ 62 dB for separating floors between dwellings
• Pre-completion testing required for new builds and conversions
• Robust detail specifications available for common construction types
• Enhanced performance (≤ 55 dB) recommended for premium developments

Professional Floor Soundproofing Systems

Floating Floor Systems

The gold standard for impact noise reduction is a floating floor that's completely isolated from the structural slab:

• Install SilentMat 15mm professional acoustic floor mat across the entire floor area
• Overlay with SilentCloud 28mm acoustic floating floor panels for high-mass structural performance
• Alternative: 33mm acoustic floor board panels for maximum impact reduction
• Turn acoustic mat up walls by 50mm to prevent sound bridges
• Install final floor finish (engineered wood, laminate, carpet) on top

This system can achieve impact sound reduction of 25-35 dB, easily meeting and exceeding Part E requirements.

Under Screed Systems

For new builds or major renovations where screed is being laid:

• Install under screed soundproofing acoustic floor underlay directly on the structural slab
• Turn underlay up walls to create complete acoustic isolation
• Lay minimum 65mm sand/cement screed or liquid screed over the underlay
• Allow screed to cure fully before installing floor finishes
• Ensure no contact between screed and walls (use edge strips)

Retrofit Acoustic Underlay

For existing floors where height allows, install acoustic underlay beneath new flooring:

• SilentCloud FFR acoustic rubber underlay for premium soundproofing and shock absorption
• 3mm acoustic underlay with 54dB noise reduction for minimal height increase
• 3mm recycled rubber acoustic underlay for eco-friendly impact insulation
• Combine with engineered wood or laminate flooring for best results

Ceiling Treatment from Below

If you cannot treat the floor above, soundproofing the ceiling below can help:

• Install 35mm acoustic hangers or 70mm acoustic hangers to create a suspended ceiling
• Fill the cavity with 100mm acoustic mineral wool
• Apply acoustic membrane for added mass
• Finish with two layers of acoustic plasterboard
• Seal all perimeters with acoustic sealant

Note: Ceiling treatment is less effective than floor treatment for impact noise but can provide 10-15 dB improvement.

Installation Best Practices

• Ensure complete coverage with no gaps in acoustic underlay
• Turn underlay up walls to prevent flanking transmission
• Use edge strips to maintain isolation between floating floor and walls
• Avoid any rigid connections between floating floor and structure
• Seal all penetrations (pipes, cables) with acoustic sealant
• Allow expansion gaps for timber and laminate flooring

Common Mistakes to Avoid

• Insufficient underlay: Standard carpet underlay won't meet Part E requirements
• Gaps in coverage: Even small gaps create sound bridges that bypass the system
• Rigid connections: Skirting fixed through floating floor to structure defeats the isolation
• Inadequate mass: Thin floating floors without sufficient mass won't control low-frequency impact
• Poor edge detailing: Contact between floating floor and walls allows flanking transmission

Specification Checklist

For new build or conversion projects:

• Structural floor assessment for load capacity
• High-performance acoustic underlay (minimum 15mm for floating floors)
• High-mass overlay boards (minimum 28mm chipboard or equivalent)
• Edge isolation strips at all wall junctions
• Acoustic sealant at all penetrations
• Pre-completion acoustic testing to verify Part E compliance

Conclusion

Soundproofing floors between flats requires professional-grade materials and meticulous installation. By using acoustic floor mats, floating floor panels, and proper isolation techniques, you can achieve excellent impact noise reduction and create peaceful multi-storey living environments that meet Building Regulations Part E requirements.