No-one wants to live with the stress caused by having to endure domestic noise pollution – which is why government policy sets out clear standards for soundproofing / sound insulation. E of UK Building Regulationsnbsp;details the soundproofing requirements for homes and schools, especially as they relate to dividing walls and floors for new builds and conversions alike.
Methods for tackling noise pollution will depend on a number of factors including accessibility, feasibility and space constraints as well as budget. In our experience, it’s rarely worth taking short cuts, because if soundproofing measures fail to meet Part E requirements, they’ll end up being a waste of time and money in the long run.
How does sound travel through floors?
Two types of sound – airborne sound and impact sound – can penetrate floors. Sound is capable of travelling through surprisingly small spaces, like gaps under skirting boards, as well as via floorboards where there’s no isolating void between ceilings and floor joists. All soundproofing techniques involve creating an insulating barrier of some kind, in addition to improving the capacity of flooring materials to attenuate vibration.
What should I consider before soundproofing floors against impact and airborne sound?
Effective acoustic insulation will help to block the transmission of noise from both airborne and impact sources. But it’s important to use the right technique for your situation, which will depend on how your home is constructed and, to some extent, whether you’re looking to silence the ingress of sound into your home – from noisy neighbours, say – or to prevent noise from escaping (if you’re a musician, perhaps). Once you’ve identified the kind of noise pollution you are dealing with, you can consider the type of soundproofing that’s most appropriate for your situation.
In general terms, soundproofing a floor will involve increasing the mass of the floor, as well as improving its ability to absorb sound energy and vibration from footsteps. When it comes to adding mass, it’s better to use varying materials – as opposed to a single material used in bulk – as they’ll insulate different frequencies of sound.
What is the best soundproofing material for floors?
Different types of floor construction – concrete, brick or timber – will require different approaches to soundproofing, and a variety of soundproofing materials.
Some solutions are independent of construction type. A floating floor provides the most comprehensive solution to the problem of sound, however it is transmitted, as it uses an interlocking system that isolates the floor from the rest of the building, so drastically reducing the passage of sound to the rooms beneath. The floor sits on absorption pads, rather than being secured with nails or screws, which helps stop vibrations from transferring through the joists. Soundproof floating floors come with a bonded layer of acoustic insulation in place. We have found that Cellecta Screedboard 28 is a reliable and popular floating floor of choice and always performs, when tested, as expected.
Soundproof floor matting / underlay can also help to reduce sound from impact and airborne sources. They are available in sheets that are ready to lay on to the existing floor and work by increasing mass and providing additional elasticity / suspension under footfall to attenuate impact sound.
What type of floor are you soundproofing?
How to soundproof timber floors
You’ll need to insulate between floor joists to reduce the transmission of airborne sound through wooden floors. Special acoustic insulation or acoustic mineral wool, as opposed to thermal insulation, which is far less dense, is essential. This should be tightly fitted between the joists, whilst leaving at least 25% free from material as an air void. To soundproof the floor above the joists, with a floating floor can be laid over the existing floorboards or acoustic matting can be used. We typically advise Cellecta Screedboard 28 for floating floors and Mutemat 2 or Mutemat 2 for acoustic matting / underlay. Both of these products are create an effective acoustic barrier to impact noise.
To ensure your floor is completely soundproofed you will also need to decouple the ceiling below from the joist system. This is to ensure impact sound does not effectively transmit into the room below. As well as providing a high density lining to attenuate airborne sound transmission. The ceiling can be decoupled via British Gypsum Resilient Bars RB1, MuteClips and furring channels, Suspended metal frame ceilings on acoustics hangers or an entire new independent timber ceiling.
How to soundproof concrete floors
Because of their mass, concrete floors provide efficient barriers against airborne noise, but they are disappointingly efficient transmitters of impact noise. Soundproofing a concrete floor requires the addition of an absorbent layer to help deaden impact. Acoustic insulation can be applied directly to concrete floors – as long as any existing flooring systems have been removed. Acoustic matting can be installed relatively easily; most mats can be cut to shape before being topped by a layer of ply and then the final finish – carpet or wooden flooring.
Ceramic tiles are more difficult to effectively insulate as joints (and possibly tiles) will crack if laid over a standard acoustic layer. Ceramic or stone tiles should be fitted over an acoustic mat designed specifically for use with this type of rigid flooring material and grouted with a cementitious product including flexible additive.
The best acoustic matting for concrete floors is the rubber crumb type and will come in a roll. We typically advise Mutemat OSF 750 – 05 where the acoustic underlay is being overlaid over the existing concrete floor. All of these floor treatments will need to be complimented by a soundproof ceiling below.
How much soundproofing is required to pass Part E of Building Regulations?
Building Regulations set the decibel rating for airborne sound resistance at 43-45dB: insulation at this level will effectively mute normal volumes of speech, TV and music through walls and floors. Impact sound – footsteps or dropped objects, for instance, on floors and stairs – is set a little higher at around 62-64dB. For more information see our pre-completion sound testing guide.
Part E building regulation failures can often be tracked back to a poorly thought-out system where quality has been skimped in exchange for a cost saving. Like water, sound will take the path of least resistance and can escape through any weak point. If, however, an effective soundproofing system has been effectively installed and yet the building still falls short of its Part E inspection, performance loss could be due to ‘flanking’.
Flanking describes the process by which sound travels along materials that are shared by adjacent structures: if sound can’t pass through the floor, for example, it might be conducted along pipes or through air pockets in joist cavities. Isolation strips around the perimeter edge of floors and on top of timber joists can reduce noise transmission considerably. In the same way, soundproof acoustic sealant can be used to close the perimeter gaps and fill any holes made during the installation of floors.
How do you soundproof an existing floor?
Although a floating floor system is the optimal solution for soundproofing, it’s not always possible to retrofit this type of system when upgrading an existing property. If you don’t want to – or can’t – lift floorboards, it’s possible to tackle noise transfer by installing soundproofing elements on top of the floor instead.
In timber floors you will need quality soundproofing matting, such as MuteMat 2, which will block some airborne sound but will primarily attenuate impact noise. The matting can be fitted before installing the final floor finish – timber, carpet or laminate. Laminate flooring in particular has become a popular choice because it’s affordable and relatively easy to fit. It is, however, a good transmitter of impact noise, so rubber underlay is essential.
How do you soundproof floors from below?
Implementing soundproofing measures on existing floors is relatively straightforward. However, if you’re enduring noise from above, you might be more interested in how you can dampen noise transmitted via the upper floor. The traditional ceiling structure, comprising timber joists covered by a plasterboard ceiling offers poor sound resistance and, by itself, won’t achieve the basic 40dB requirements of the Building Regulations for bedrooms.
If there’s sufficient headroom, the ideal solution is to create a secondary suspended ceiling beneath the existing floor joists. This ceiling would be supported by new timber joists spanning the walls and with a gap of at least 25mm between it and the joists above. With acoustic sealant around the perimeter edges, this should achieve airborne resistance of 45dB or more. Alternatively, acoustic insulation could be installed between the joists (100mm) before upgrading to a heavier plasterboard with a denser mass.
Can you soundproof under floorboards?
If you’d prefer to add the soundproofing insulation in the space under the floor, you’ll need to lift the floorboards first. This may sound like a daunting proposition but it’s worth considering as under-floor soundproofing with an acoustic membrane and special mineral wool can be highly effective at reducing airborne sounds.
Acoustic mineral wool should be installed between the floor joists: 100mm of acoustic floor insulation with a density of between 60kg/m³ and 80kg/m³ is recommended to optimise the soundproofing between floors. If you intend to scrap the existing boards, you could then choose to fit high-performance acoustic board directly on to the joists. These boards incorporate a 15mm foam layer bonded to a 22mm chipboard and are highly effective acoustic insulators. However, refitting the original floorboards will also provide some insulating properties that can be enhanced by topping with an acoustic mat.
Soundproofing floors in summary
No matter what floor type you have – concrete or timber – noise will always find a way to travel through unless you can attenuate it. Identifying the type and level of noise is the first step. Once you’ve diagnosed the cause – whether it’s primarily airborne (voices, TV) or impact-related (footsteps, banging), you can then assess the best soundproofing options. Bear in mind that attenuating airborne noise will involve the installation of high-density acoustic materials and decoupling elements of the soundproof floor system. Whilst impact noise requires an elastic layer within the soundproof floor system. Because most noise pollution will comprise a mixture of airborne and impact sources, it’s likely that you’ll need a solution that tackles both.