Does Acoustic Underlay Work? The Honest Answer

Apr 7, 2026

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

If you've been researching acoustic underlay, you've probably seen impressive decibel figures on product pages and wondered: does acoustic underlay actually work in the real world? The honest answer is yes — but with important caveats about expectations, installation quality, and which type of noise you're trying to reduce. This article gives you the unvarnished truth.

What Acoustic Underlay Is Designed to Do

Acoustic underlay sits between your subfloor and your floor finish (wood, LVT, laminate, carpet). Its primary job is to reduce impact noise — the sound of footsteps, dropped objects, and chair movement that travels through the floor structure and radiates into the room or flat below.

It does this through two mechanisms:

  • Resilience — the underlay compresses slightly with each footstep, absorbing the impact energy before it enters the building structure
  • Mass — denser underlays add mass, which resists sound wave transmission

The Real-World Numbers

Laboratory tests measure acoustic underlay performance as ΔLw (Delta Lw) — the weighted improvement in impact sound insulation over a bare concrete reference slab. Here's what our products achieve:

These are meaningful, independently tested numbers. In the real world, a 10dB reduction in impact noise is perceived as roughly half as loud by the human ear. A 20dB reduction is dramatic — the difference between clearly audible footsteps and a very faint sound.

Does It Work for Neighbour Noise?

This is where we need to be honest. Acoustic underlay is highly effective at reducing the impact noise that you generate — protecting your downstairs neighbours from your footsteps. If your upstairs neighbour installs acoustic underlay under their floor, your problem is largely solved.

However, if you're trying to reduce impact noise coming from above you by treating only your ceiling (without access to the floor above), acoustic underlay in your floor has no effect on that specific problem. In that case, a resilient bar ceiling system below is what you need.

For airborne noise (music, TV, voices) from neighbours, acoustic underlay provides limited benefit on its own — airborne sound reduction requires mass, and most underlays are relatively thin. For serious airborne noise problems, a higher-mass system is required.

Where Acoustic Underlay Excels

  • New flat conversions — achieving Part E compliance (L'nT,w ≤ 62dB)
  • Flats where you have access to the floor — protecting downstairs neighbours
  • Homes with children — dramatically reducing footstep, running, and playing noise
  • Open-plan spaces — LVT and engineered wood without underlay can sound hollow and noisy; acoustic underlay solves this completely
  • Gym floors — preventing heavy equipment impact from transmitting through the building

The Installation Factor

Acoustic underlay only works as well as the installation allows. The most common performance killers are:

  • Gaps between underlay sheets — sound travels through the path of least resistance
  • Rigid connections at walls — the floor finish must be free-floating, with expansion gaps sealed with acoustic sealant, not foam
  • Wrong underlay for the floor type — some underlays are not suitable for under-screed use (our 6mm rubber pro is specifically engineered for this)

Our Verdict

Acoustic underlay works — genuinely and measurably. For reducing impact noise from your floor, it's the single most cost-effective acoustic investment you can make. For a complete UK flat solution, combine our 6mm Recycled Rubber Pro (74dB) with a resilient bar ceiling below for a comprehensive, Part E-compliant result.

FAQs

Does acoustic underlay reduce TV noise from downstairs?

Not significantly — TV noise is airborne, and most acoustic underlay is designed for impact noise. You need a higher-mass floor system (like AcoustiLay 8 with 58dB airborne rating) to meaningfully block airborne noise.

Is more expensive acoustic underlay worth it?

Yes — the difference between 3mm budget underlay (54dB) and our 6mm Pro (74dB) is 20dB, which is enormous in acoustic terms. For any flat, Part E project, or serious noise problem, the higher-spec product is worth the investment.

How do I know if my acoustic underlay is actually working?

Ask someone to walk on the floor while you listen from below. Compare before and after installation — the difference is usually immediately audible. For formal verification, commission an acoustic test (required for Building Regs notifiable works).
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