Excessive noise distracts us and interferes with sleep, relaxation, productivity, and even our health. Acoustic building materials can help us create spaces that promote well-being and aural harmony.
Soundproofing is most effective during construction but can also be added to existing structures. These treatments include resilient sound channels which decouple the drywall from the framing and joists to reduce vibrations.
Mass and Density
The basic principle behind soundproofing is that vibrations are stopped from passing through walls by adding mass and density. Most of the time this is done by adding a heavy material to the wall construction. This might be something as simple as a thick layer of mineral wool insulation or acoustic Basotect foam, designed specifically for this purpose. This product is known as a’sound blocking foam’ and it reduces both airborne transmission (from one room to the other) and structural transmission (from one floor to another). It also helps with improving internal acoustics which is often an issue in modern buildings.
The acoustic performance of the product is determined by its mass and thickness and can be governed by a relationship called ‘Mass Law’ which states that the higher the mass per square inch, the greater the acoustic performance. This property is also dependent on the frequency of the sound being reduced, with higher frequencies needing a larger mass to be effective.
Resilient isolation channels are a popular method for decoupling drywall from the structure of a building, these are timber battens or aluminium metal rails that are placed over and glued to the acoustic insulation. They work by reducing the transfer of vibration from joists to the drywall and can be supplemented with acoustic hangers which further reduce the transmitted vibration.
De-coupling
Soundproofing focuses on stopping the transfer of vibrations between structures. One way to do this is by decoupling the materials in a wall from each other. This can be achieved by using acoustic insulation or specialty framing techniques like staggered stud walls or resilient isolation channels.
Another important element is mechanical decoupling which works by breaking the direct path that sound can travel through a structure by inserting gaps between the materials and structural elements. This can be done by using acoustic clips or resilient channels as well as by using specialty framing techniques such as the use of staggered studs, double drywall and acoustic insulation like mineral wool.
A third aspect is absorption which involves building materials that absorb rather than reflect sound. Hard surfaces such as gypsum board, concrete and solid wood tend to reflect and transmit sound while soft materials such as carpet, foam and sound absorbing insulation are very effective at absorbing and diffusing sound waves.
Absorbent materials can also be used to improve speech intelligibility in a space by eliminating echo and reducing room resonance. Adding sound absorbing panels and acoustic insulation to a new or existing space can dramatically improve the quality of sound in that space.
Constrained Layer Damping
Many types of acoustic insulation include absorptive materials designed to absorb sound rather than reflecting it. For example, acoustical ceiling tiles are usually made of thick fabric which absorbs the sounds and stops them from transferring between rooms. Thick carpet and curtains are also highly absorptive.
Other types of soundproofing insulation materials use the de-coupling principle to separate structural components. Resilient channels ranging from simple timber battens to aluminium metal rails can be installed between wall and ceiling studs. They effectively pack out the space normally filled by the studs, joists and framing members to reduce noise transmission.
The decoupling principle is further improved using constrained layer damping. This type of material converts sound energy into heat through friction and weakens the wave, thus helping to reduce flanking transmissions between structures. It’s often used to complement decoupling when soundproofing existing buildings or to improve the performance of an acoustic insulation product.
In addition to helping us live and work more comfortably, acoustic building materials play a critical role in protecting our health. Studies show that excessive noise has been linked to reduced sleep quality, stress levels and cognitive performance. Good acoustic performance is therefore increasingly important for homes, offices and learning environments. The UK government has passed legislation (Building Regulations Part E) to improve the acoustic performance of new and refurbishment housing.
Absorption
Despite soundproofing materials typically being made of hard and dense materials to help decouple walls and increase the weight of the wall, there is an important role that absorption plays in reducing noise issues. The reason is that not all noise is airborne and that some, such as low frequency sounds, will travel both through the structural vibration of the building and through the air. Absorption helps reduce this transmission by absorbing these sound waves to prevent them from leaving the room.
Sound absorbing products such as acoustic panels, baffles and stretched fabric systems are designed specifically to absorb sound waves rather than reflecting them back into the room. This lessens reverberation, noise build-up and makes speech intelligibility better in offices and schools.
One easy way to think of it is that sound is a lot like water. If you built an aquarium to hold water would you use glass or sponges? Sponges will absorb it but won’t stop it from seeping out of the tank. Glass and good seals will keep the water in and control it.
When it comes to soundproofing you can’t stop all noise but blocking and absorbing is the best way to solve many of these problems. Whether it’s excessive noise in an office, poor speech intelligibility in a classroom or an annoying echo in an open plan space – our massive product catalogue has you covered with a solution.