How to soundproof a floor
Adding acoustic insulation to the floor will help to control sound transmission from airborne noise such as loud music and TVs, along with impact noise which occurs when objects, or people, hit or move across the floor. Deciding on the right soundproofing material for your floor will depend on the structure of your home and whether you want to avoid noise getting in because of noisy neighbours or prevent noise from getting out because you are a musician.
This article will explain how to soundproof a floor and suggest some of the best products available to reduce noise pollution through the floor.
What to consider before starting
The first thing to assess is the make-up of the floor along with the adjacent walls for flanking.
Flanking occurs when a sound takes an alternative route, so this will mean investigating to find out the exact source of the sound if it is moving to adjacent walls.
The construction of each property will vary. Flats and apartments are often made of concrete and period houses will be comprised of brick and timber.
Timber-constructed houses will feature structural wooden joists which will feature a large space beneath of up to 2 metres. Existing floorboards could be traditionally nailed down exposed timber. Modern builds may use ply or chipboard.
In properties made from concrete mean soundproofing acoustic insulation can be applied directly to the concrete once the existing flooring system has been removed. When you look underneath the structural flooring there are large timber battens suspended from the concrete slab. A joist filler will be in this cavity which would look similar to a structural wooden joist.
Soundproofing under hard floors
Once you know the type of noise pollution you are dealing with, then you can think about the type of soundproofing you can install in the floor.
Airborne sound: To reduce the transmission of airborne sound through wooden floors the best solution is to insulate between the floor joists using acoustic insulation. Acoustic insulation is different to thermal insulation which is far less dense and lacks the properties to ensure efficient soundproofing of the floor.
To ensure an increased level of soundproofing use a product like Rockwool RWA45 Acoustic Insulation Slabs which is ideal for suspended ground floors. This also meets the requirements of Part E of the Building Regulations at 100mm 45kg/m³.
Impact Sound: This is caused by the vibration that comes from an object hitting the floor, and the level of noise generated will depend on how hard the item impacts the surface. The best two solutions available to reduce impact noise is using floating floors or acoustic matting. This will help with both concrete and wooden floors, although you will have to take into consideration things such as floor finish, height and any building regulations that need to be met.
Acoustic matting
Karma Acoustic Overlay Plus Board is commonly installed above a timber deck and underneath floor finishes such as wooden floors, carpets etc. Acoustic matting is a great way of soundproofing the floor against impact noise.
This is a relatively easy type of soundproofing to install as the mats can be cut into shape using a sharp knife, before being positioned in a brick-like pattern. To reduce movement and potential damage to the edge of the floor finish a layer of 9mm ply should be laid over the matting.
Floating floors
This means the floor is not mechanically held in place with either screws or nails. Instead, floating floors use an interlocking system with tongue and groove edges that easily slot together. Soundproof floating floors come with a resilient layer already bonded to the underside of the surface.
The isolation of the floor from the structure of the building will enable the reduction of sound that passes through the floor and joists into the room underneath. Karma Soundlay Plus is a high-performance acoustic insulation system that can be used on either concrete or floating floors and helps to reduce impact sound.
Soundproofing panels
Acoustic or soundproof floor panels offer another way to reduce impact or airborne sound. They come in approximate sizes of around 10 square feet, similar to the Karma Acoustic MassPanel which can either be laid on the existing floor or onto the joists themselves. This increases the mass of the flooring structure and absorbs the soundwaves making the transmission of noise far more difficult.
Karma Acoustic Easy Panel is another option available that will perform equally as well. It is sized at 0.96m²and provides strong acoustic insulation in the floor, protecting the space underneath from impact and airborne noise.
Using insulation materials
Using acoustic insulation slabs to control the movement of impact of airborne sound is a common method that ensures effective results. Rockwool RWA45 Acoustic Insulation Slabs are used in walls, ceilings and floors in both domestic and commercial properties.
Care should be taken when purchasing insulation material for the first time. Thermal insulation rolls are not suitable for acoustic blocking as the material is not dense enough to absorb sound. However, Earthwool Acoustic Roll provides a high level of sound absorption and can be used in the floor to dampen noise.
