Acoustic resilient flooring
Key takeaways
- There are two separate acoustic problems and they need different answers. Impact sound insulation protects the room below; sound absorption improves the room you are standing in.
- Acoustic vinyl and acoustic LVT solve the first, not the second. A hard floor with an acoustic backing still makes a room sound hard.
- The dB figure on a data sheet is a laboratory value for the product. What the building achieves depends on the structure, the workmanship and the flanking paths.
- Every acoustic backing is a compressible layer, so indentation resistance falls and substrate defects show more readily. That trade-off is unavoidable and should be designed for.
- Where the requirement is a regulatory one, the target is set by the building type and it should be confirmed in writing before a product is selected.
What is acoustic flooring?
Acoustic flooring is a floor finish built with a resilient layer that reduces the noise transmitted into the space below when the floor is walked on, dropped on or scraped. In resilient finishes this is a foam, cork or cross-linked backing bonded to the underside of a vinyl sheet or an LVT, or a separate acoustic underlay laid beneath the finish.
The term gets used loosely for anything that makes a building quieter, which causes a specific and expensive confusion. A floor that reduces impact noise for the neighbours below does very little for the person standing on it and a floor chosen to make a room sound calmer may do nothing for the regulatory requirement it was supposed to satisfy.
Impact sound and sound absorption are different problems
Impact sound is structure-borne. Footsteps, dropped objects, trolley wheels and chair movement put energy directly into the floor construction and it radiates as noise into the space below. The fix is a resilient layer between the source and the structure, which is exactly what an acoustic backing is. It is measured as a reduction in weighted impact sound pressure level, quoted in decibels and usually written by manufacturers as delta Lw. Airborne sound insulation is a separate measurement, expressed for a finished construction as DnT,w plus Ctr and it is not improved by a floor covering in the same way.
Sound absorption is airborne and it is about reverberation within the room. Speech, keyboards, crockery and machinery bounce between hard surfaces and build into a wash of noise that makes a space tiring and hard to work in. A resilient floor with an acoustic backing does almost nothing about this, because the surface is still hard and reflective. The fix is a soft, fibrous or perforated surface, which in flooring terms means carpet.
The practical consequence is that these two requirements are satisfied by different products. An open plan office above a residential unit may need both and it will need an acoustic resilient finish or carpet with an acoustic backing for the impact requirement plus ceiling and wall treatment for the absorption. Getting this wrong at concept stage is one of the most common acoustic failures in a fit-out. The wider material comparison sits under commercial vinyl vs LVT and the sports hall case, where impact absorption is a separate requirement again, under sports hall flooring.
What the dB figures actually mean
Acoustic resilient products are quoted with a reduction figure – commonly somewhere between 14 and 22 decibels for an acoustic vinyl or LVT, depending on the backing. Reading those numbers correctly matters.
The figure is a product improvement measured in a laboratory over a standardised concrete floor. It describes what the covering contributes, not what the building will achieve. The building’s performance depends on the mass and construction of the floor slab, the ceiling below, the presence of a floating screed and how well the perimeter and penetrations were detailed.
Where a regulatory or contractual target applies, the target is normally a field-measured figure for the finished construction rather than a product figure. That is a different measurement taken on site after completion and a project that specifies the product number and assumes the building number will pass is taking a risk. On projects where the target is contractual, the acoustic consultant should confirm the whole build-up rather than approving a floor finish in isolation.
The other thing worth knowing is that decibels do not add arithmetically. Two products each offering a good reduction do not combine into the sum of the two and stacking an acoustic underlay beneath an already-backed acoustic finish rarely delivers what the numbers suggest while reliably making the indentation problem worse.
Where the requirement comes from
In England and Wales, impact sound performance between dwellings and between rooms for residential purposes is a building regulations requirement and it applies to student accommodation, care homes, hostels, boarding houses, halls of residence and residential conversions as well as to flats. Some hotel developments are designed to equivalent acoustic standards depending on how the building is classified, so the classification should be confirmed rather than assumed. Scotland and Northern Ireland have equivalent provisions in their own technical standards.
Schools carry their own acoustic requirements covering both sound insulation and reverberation, which is why an education flooring specification often has an acoustic clause on a corridor floor where nobody expects one.
Beyond regulation, the requirement usually comes from the lease or the landlord. Commercial fit-outs in multi-tenant buildings are routinely required to meet a landlord’s acoustic specification for the floor build-up and that document rather than the regulations is what the floor has to satisfy. It should be obtained before a product is chosen, because landlord specifications sometimes name products or build-ups directly.
The indentation trade-off
Every acoustic resilient floor works by having something soft in it and something soft compresses under load. That is not a manufacturing shortcoming, it is the mechanism.
The consequence is that acoustic builds have lower indentation resistance than their standard equivalents. A heavy static load – a filing bank, a server rack, a hospital bed leg, a display fixture – left in place will leave a permanent mark in a way it would not on a standard build. Rolling loads such as trolleys and castor chairs also work the surface harder, because the material deflects and recovers with every pass.
There are three practical responses. Check the residual indentation classification against the actual equipment rather than the room type. Spread point loads with proper feet or load-spreading plates at the known locations. Where an area has both a genuine acoustic requirement and heavy static loading, resolve it in the build-up – a floating screed or an acoustic cradle system beneath a standard finish – rather than asking the floor covering to do both jobs.
Substrate sensitivity
The second trade-off is that acoustic backings conform to the substrate rather than bridging it. A standard vinyl or LVT is generally more forgiving of a small imperfection; a soft-backed product presses into it and the defect reads through as a shadow under raking light or as a visible dip.
That raises the preparation standard rather than lowering it, which is counterintuitive and catches people out. A properly applied smoothing compound over a sound, primed substrate is more important under an acoustic product than under a standard one, not less. Guidance sits under subfloor preparation.
Adhesive selection also changes. A compressible backing behaves differently in the adhesive bed and the manufacturer usually nominates a specific adhesive and open time for the acoustic version of a product. Substituting the standard adhesive is a routine cause of a floor that looks fine at handover and telegraphs within a season.
Flanking transmission – the thing that undoes a good floor
A floor finish can only interrupt the path that runs through it. Sound also travels around the floor, through walls, columns, service penetrations and the perimeter junction and those flanking paths frequently dominate the result.
The practical points are perimeter isolation, service penetrations and rigid bridges. Where a floating build-up is used, the resilient layer must be turned up at the perimeter so the screed does not touch the wall and skirtings must not clamp the two together. Pipes, conduits and drains passing through the floor need to be sleeved and sealed resiliently rather than grouted solid. Any rigid path from the finished floor to the structure – a fixing, a mortar bed, a spilled dab of adhesive under an isolation strip – short-circuits the whole build-up.
This is why a building can fail a post-completion sound test with a correctly specified floor covering laid correctly. The finish did its job; something else provided a bypass. It works the other way too. A resilient floor covering cannot compensate for an inadequate separating floor construction, so where the structure itself is marginal the answer lies in the build-up rather than in the finish.
Acoustic carpet and the absorption answer
Where the problem is how the room itself sounds, carpet is the flooring answer and nothing hard comes close. A cut pile or a loop pile on a suitable backing absorbs mid and high frequency sound directly, which is why open plan offices, call handling floors, libraries and hotel corridors still specify it despite hard finishes being more fashionable. How that plays out zone by zone across a workplace is covered under flooring for offices.
Carpet also performs well on impact sound and a backed carpet tile can exceed the reduction figures of many acoustic resilient products, so in a building that needs both, carpet solves two problems with one specification. Where a hard finish is wanted for appearance or cleaning, the absorption has to be provided in the ceiling or the walls and that cost has moved to another package rather than disappeared. This sits alongside the wider specification for commercial carpet and carpet tiles.
What to confirm before you specify an acoustic floor
Separate the two requirements in writing before anything else. Establish whether the target is a regulatory field figure, a landlord specification or simply a comfort ambition, because those need different evidence. Confirm the whole floor build-up rather than the covering alone. Check the residual indentation classification against the real equipment. Confirm the adhesive and preparation the acoustic version of the product requires. Confirm who owns the flanking details, because that is where the result is usually decided.
Acoustic resilient products are made by manufacturers such as Polyflor, Altro, Forbo, Gerflor, Tarkett and Amtico and a specialist contractor matches the build-up to the acoustic target, the loading and the substrate. Listing a manufacturer here does not imply a partnership, approval or accreditation.
Surface Specialists is a network of vetted specialist contractors covering commercial vinyl, LVT, commercial carpet and subfloor preparation. Tell us the acoustic target, the loading and the programme and we match the project to a contractor who works in that environment. Get in touch to arrange a site survey.
Frequently asked questions
What is acoustic vinyl flooring?
It is a commercial vinyl manufactured with a resilient foam, cork or cross-linked backing that reduces the impact noise transmitted into the room below. It is specified where footfall, trolleys or dropped objects would otherwise be audible in the space beneath, typically in hotels, student accommodation, care homes, apartments and multi-tenant offices.
Does acoustic flooring make a room quieter?
It makes the room below quieter, not the room you are standing in. An acoustic backing addresses structure-borne impact noise. Reverberation within the room comes from hard reflective surfaces and needs an absorbent finish, which in flooring terms means carpet, or absorption provided in the ceiling and walls.
What dB reduction does acoustic vinyl give?
Products commonly quote somewhere between 14 and 22 decibels depending on the backing, but that is a laboratory improvement figure measured over a standard concrete floor. What a building achieves depends on the slab, the ceiling below, the perimeter detailing and the flanking paths and regulatory targets are normally measured on site for the finished construction rather than taken from a product data sheet.
Is acoustic LVT available?
Yes. Acoustic LVT is manufactured with a bonded resilient backing and separate acoustic underlays are also available for use beneath standard LVT. Both approaches lower indentation resistance and increase sensitivity to substrate defects, so preparation standards and load points need more attention than they would with a standard build.
Does acoustic flooring dent more easily?
Yes and unavoidably so, because the resilient layer that provides the acoustic performance is a compressible one. Residual indentation classifications for acoustic builds are lower than for their standard equivalents, so heavy static loads should be spread with proper feet or load-spreading plates and the classification checked against the real equipment.
Do I need acoustic flooring in a commercial building?
It depends on what is below. Impact sound performance is a regulatory requirement between dwellings and rooms for residential purposes, which includes student accommodation, care homes and hostels. Some hotel developments are designed to equivalent standards depending on the building classification and schools carry their own acoustic requirements. In multi-tenant commercial buildings the requirement usually comes from the landlord specification, which should be obtained before a product is chosen.
Why did our floor fail a sound test when the product met the specification?
Usually because of flanking transmission. Sound travels around the floor through walls, columns, perimeter junctions and service penetrations and any rigid bridge between the finished floor and the structure short-circuits the build-up. A correctly specified and correctly laid floor covering can still fail if the perimeter is not isolated or a penetration is grouted solid.