Sound proofing between floors
There are two types of noise you have to consider when insulating between floors:
which travels through the atmosphere and passes through walls, floors and ceilings. To reduce the effect of airborne noise you will need to add barriers of different density to protect against different sound frequencies.
which is sound that arises as a result of materials banging each other to cause vibration to pass on through the materials themselves; like shoes banging on floors, doors slamming or chairs moving across a solid floor. To reduce the effects of impact noise, you need to add an intervening barrier that will absorb rather than pass on or resonate the vibration.
Unlike walls, floors will also transmit impact sound as well as airborne sound.
Typically in residential buildings, floors consist of timber joists with chip boarding on top and a thin plasterboard ceiling below. This will not offer much protection against penetrating noise an especially not impact noise. And by itself will not comply with the minimal Building Regulation standard requirement for bedrooms of 40dBs.
You have three basic solutions:
- Insulate with materials under floorboards between joists, using at least 100mm of mineral wool of at least 10kg/m3 Look out for specially fabricated acoustic quilt.
- Build in a false suspended ceiling beneath the floor joists. Use sound quality plasterboard and acoustic silicone sealant and/or tape to seal perimeter edges.
- Lay down overlays, essentially over-floor acoustic boarding or matting. This can include specialist screedboards, such as DECKfon ScreedBoard 28, especially where under floor heating requires a heat conductive covering material. Use composite boards where the different densities have been designed and tested to cut out different sound frequencies. This will help impact as well as airborne noise.
Impact noise requires a barrier to reduce transmitted vibration. High density matting (for example, DECKfon Utramat) or acoustic boarding (for example DECKfon ScreedBoard 28) on top of existing floorboards and then finish off with carpet, tiles or timber over the top.
Over floor solutions will also work for airborne noise. DECKfon ScreedBoards or DECKfon Ultramat absorbs airborne noise due to the composite nature of their construction. If the noise is really extreme, you can take up floorboards or add false ceilings, and pack with acoustic quilting, but in most instances, over-floorboard solutions will suffice to reduce noise to acceptable levels and meet Part E regulation requirements.
Does it matter if I use carpet or hard floor finish?
Both DECKfon ScreedBoard range and Ultramat products will work for carpet solutions. And our ScreedBoard range will work with tiled or wooden and laminate boarding laid on top.
What about ‘flanking’ noise and transmission?
Flanking noise is sound transmitted indirectly through and around materials that form the construction of a property, and is most typically the result of ‘impact’ noise as vibration passes along and across the fabric of a building. Noise will follow paths of least resistance, and can amplify in void areas before passing through subsequent barriers. It is especially a problem where intervening walls are lightweight, which is why building regulations now stipulate ‘correct’ density blocks in the construction of modern flats and multi-occupied buildings.
The best way to prevent flanking noise is to fill empty areas, or intervene in the connection between the different fabrics of a building, by using an acoustic barrier. This may well require you to get under the floorboards, for example to lay acoustic quilting in voids such as between ceiling joists. You might also need to fill gaps in walls, using an acoustic sealant. And importantly, use a perimeter edging (such as our Yelefon FS30), to separate hardwood flooring from surrounding walls.
Is soundproofing difficult to install?
Most over floor products are easy to install if you have some DIY experience. Check out installation videos and download installation guidance. As staff can also provide direction and advice, or point you to where you can obtain further more detailed assistance.
You may find the products you need for sound proofing between floors at https://acousticfloorinsulation.co.uk But simple singular solutions might not be the answer, so if you have a complex or unusual situation, we’d recommend you speak directly to our partners at Cellecta on 01634 292277.