Soundproofing 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.

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.

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.

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 acoustic 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.

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.