On large residential and commercial projects sound travel and acoustics are very important. In a large open plan family home with small children there will be a lot of noise, and parents do not want this to travel all through the house. Similarly, restaurants and other public spaces do not want echoes and sound reverberation to disturb their diners and customers, so space planning and the choice of wall covering is an important factor in reducing echoes, sound travel and unwanted noise. Large expanses of glass, stone or exposed brickwork that is included in a building plan for aesthetic reasons exacerbates the problem of noise reverberation and travel, so it is even more important that the sound is controlled in another way.
Acoustic plaster and soundproof plasterboard are both good ways of dealing with this problem and the choice between the two methods comes down to cost and the space that needs treating. Spaces with curves and unusual wall heights are more suited to the acoustic spray applied plaster option, as there is no need to cut boards down or struggle to achieve a smooth curve from individual pieces of soundproof plasterboard. More standard rooms, like reading rooms in libraries or in a normal domestic house are suitable for the board system. It is important though, when using a soundproof plasterboard, that the plaster layer used on top is acoustically transparent, otherwise the only effect will be soundproofing that room from the rest of the building and the internal acoustics can still be undesirable.
Acoustic plaster and complete plastering systems are available from many manufacturers, and some are comprised of a double layer system with a substrate bonded coating that absorbs sound and a plaster coating that allows sound waves through to the absorbent layer. Armourcoat is a new system to the UK, and was launched in March across the country. It uses a mineral wool layer applied directly to the substrate, with a surface coating of marble based plaster which allows sound to penetrate to the absorbent mineral wool beneath. The marble plaster coating can be coloured to reduce the need for further decoration as it leaves a smooth and desirable finish. In testing the 30mm system achieved a class C rating for airborne sound absorption, and the 50mm system achieved a class A rating.
Stil-Acoustics offer a slightly different system with only one layer of coating needed. The acoustic plaster is either sprayed directly to the substrate in a variety of finishes (Acospray) or supplied as plasterboard (Acoplaster). As with the Armourcoat system it is available in different colours, and achieves a class A rating at 35mm thickness.
Other manufacturers of acoustic plaster systems are Fellert, Terraco and Quietstone, although not all these manufacturers make wall coverings – Quietstone is an acoustic ceiling solution rather than one that can be applied to walls as well. These types of acoustic plaster systems are ideally suited to addressing problems with sound levels in spaces such as offices and restaurants, that may have large expanses of glass or tiles and very little vertical wall space that can be treated with an acoustic plaster.
The big benefit to using an acoustic plaster system is that a free-flowing space can be designed with no need for clever baffles and sails to redirect and absorb unwanted noise. On new builds especially, you may find that the architect has specified the use of one of these systems in order to be able to keep a very open plan main space that does not have to be engineered around sound issues as a primary concern. They are also ideal for use in a space that has acoustic issues but where it is not appropriate to redesign the flow of the space to install soundproofing features. Most of these systems are spray applied by machine, which is yet another good reason to get into machine plastering, as you will be able to offer these soundproofing and noise reducing plasters alongside the standard range of surface finishes.