Soundproofing windows and secondary glazing

According to the World Health Organisation, the impact of noise pollution and particularly disturbed sleep can be enough to raise blood pressure, increase the chances of heart disease and even lead to premature death. Its recent campaign focussing on the impact of products in our homes found that 40 per cent of Europe’s population is exposed to noise levels in excess of 55dB. The average washing machine has a recorded sound level of 70dB, refrigerators average at around 50dB refrigerator while in some instances food processors can reach up to 90dB. 

Sound proofing and windows

Windows may not be able to provide a solution to noise inside the home but they can make a significant contribution to the reduction of the impact of noise outside it – roads and traffic, aircraft and many others. This is done through the use of acoustic glass. This uses multiple layers and different thicknesses to disrupt sound waves as they travel from one side of the glass and through the glazing unit to the other. Put very simply, it creates more hurdles for the sound wave to pass through, reducing the amount that ultimately gets through. If the concept is simple, the technology which underpins it, is much more complex. In splitting the glass into multiple layers you have to bond it back so that it performs as a single ‘sheet’. This is where the use of Polyvinyl butyral comes in. It forms an adhesive bond between ultra-thin sheets but also creates an additional layer for sound to pass through, delivering a further dampening effect. It also makes bonded acoustic glass much tougher and durable than standard glass, making it harder to break, keeping would-be intruders, out. The exact specification of acoustic glass is defined by the type of noise that you want to keep out. Road noise, your neighbour’s ‘yapping dog’, the kid next door’s drum kit – they all create different sound waves and the combination of glass sheets and their collective thickness needs to be adjusted according to the noise you’re trying to block. The critical thing is that the glass which makes up double or triple glazed units should not only be as thick as possible but also be of differing thicknesses. The additional sheets of glass used in triple-glazed units for example, won’t necessarily make things quieter because the line of travel of sound won’t necessarily be disrupted. In bringing different thicknesses of glass together in a single unit, sound is deflected and the line of travel is disrupted, keeping noise out. It's definitely worth doing your research. 

The big glass manufacturers, for example Pilkington and Saint Gobain offer lots of guidance online. There are also lots of good installers out there – we would like to think we’re one – who can talk you through it. It does require a slightly more specialist understanding so it’s also worth double checking that what you’re being told adds up. Soundproofing can be achieved with both new windows and secondary glazing, you can find more information on soundproof windows