Pre-completion sound testing is the on-site acoustic measurement required to demonstrate that a new residential building or conversion meets Part E of the Building Regulations before it can be occupied. Tests measure airborne sound insulation (through walls and floors) and impact sound insulation (through floors). The pass thresholds for new builds are DnT,w + Ctr ≥ 45 dB for airborne sound and L'nT,w ≤ 62 dB for impact sound; for conversions, 43 dB and 64 dB respectively. Testing must be carried out by an accredited body: NOVA Acoustics holds UKAS accreditation (No. 8568) for sound insulation testing. If a test fails, building control sign-off cannot be granted until remediation is completed and a passing re-test is achieved.
Do I simply add mass to Walls and Floors to soundproof?
In today's open plan living the need for sound insulation has become increasingly important.
There are many complex elements that are involved in the soundproofing of a building. All of these elements work together to help reduce noise and vibrations. Although adding mass is one of these important elements, there are many other factors which are also incredibly important. Below we explore the importance of decoupling, absorption, damping and mass, and how they all play a key role in helping to isolate sound in buildings.
The importance of absorption
Sound absorbing materials play a vital role in providing sound insulation to a room. The problem with modern homes is there is often trapped air within the wall cavity, and it is this air that resonates and makes a noise, or helps to amplify noise. Wall cavities are responsible for carrying noise across one wall through to a joining room. One useful material to insert into the wall cavity to help solve this problem is fibreglass, as this will help to absorb any sound. Other choices include wool, cellulose, and even recycled cotton.
The first step is decoupling
Decoupling should be the very first step in soundproofing any room. A simple definition of decoupling is that of separating objects, and in terms of soundproofing, this means isolating sound between floors, ceilings and walls. Sound travels from floor to ceiling, as there is a natural pathway that allows the sound to travel. Decoupling breaks this chain. Some decoupling methods include the use of soundproofing clips, a resilient channel, staggered and double studs walls.
Damping reduces sound resonance
Damping is the process used to reduce any sound resonance within a room. This is done in combination with absorption and redirection. Very often damping is achieved during the construction of buildings with the installation of dead walls, as they do not vibrate. It is this vibration that increases noise levels within a room. Installing thick doors can also help to aid with the damping of a room, and this includes hidden doors which naturally provide additional mass and concealment, helping to minimise sound transfer. Damping won’t be very beneficial by itself, but it is effective when absorption is used within the structure of the walls.
Adding mass
Finally, we come full circle and back to the importance of adding mass. There are two important factors to consider when adding mass. That of what type of material to use and where it should be placed. In terms of insulating sound in buildings, then this is done primarily through the use of adding plywood, cement board and drywood to walls. The idea here is to make the walls as heavy and thick as possible. Although adding mass to both walls and ceilings will decrease sound vibration, it will not stop bass sounds from being heard.
It should also be noted that adding mass to any room is a good way to provide insulation, making the room more energy efficient and environmentally friendly.
Looking for more information on floor soundproofing?
We have covered floor soundproofing in more depth within a dedicated guide, where we discuss the products needed and how to pass Part E of the Building Regulations.
Looking for more information on wall soundproofing?
We have also covered wall soundproofing in more detail within a dedicated guide on our blog. We have covered how to soundproof timber, brick and steel walls.
Conclusion
There are four components that help to provide sound insulation in buildings. Decoupling, absorption, damping and adding mass. All help to isolate sound with mass playing a vital role.
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