Noise pollution is a serious issue and can be damaging to a person’s health due to increased levels of stress and disturbed sleep. The transmission of external noise is usually part of a planning requirement, but shouldn’t be overlooked when planning permission is not required for small-scale renovations which involve the replacement of a window or door.
It is true that the acoustic performance of a wooden window is enhanced by additional layers of glazing. The addition of an extra pane (i.e. double glazing) within a window would appear to be the best option to reduce noise passing through the window as noise is absorbed as it travels through the airspace between the two panes. However, this is not the only factor to be considered when evaluating acoustic performance.
In this article, George Barnsdale highlight all of the key factors that should be considered when evaluating the acoustic performance of any wooden window. All reputable manufacturers will be able to provide guidance on this, to ensure you get the best fit for your home and location.
The thickness of the individual pieces of glass
Generally speaking the thicker the glass the better the enhanced acoustic insulation, but what is often overlooked is the high performance given by a selection of suitable glass thicknesses. It’s important to consider differing the thicknesses of individual glass panes by at least 30% in order to minimise acoustic resonances within the glazing unit. For example, a 4mm pane when combined with a 6mm pane will perform as well as 2 x 6mm panes, at least.
The laminate between the individual pieces of glass
Laminated glass is often specified for its sound damping characteristic, rather than for its safety and security performance. This is due to the PVB (polyvinyl butyral) interlayer that helps to reduce the passage of sound. Further improvements can be achieved by using special acoustic interlayers which may provide an additional 2-3dB reduction in sound.
Higher noise frequencies are more affected by the air performance of the wooden window rather than the mass of the glass. Windows that have a very high air penetration performance tend to perform well acoustically. All reputable window manufacturers will be able to provide you with this performance data.
Quality of Installation
It goes without saying that a poorly installed window will provide poor acoustic performance. Ensure that your chosen installer is complying with BS 8213-4:2016 Code of practice for the survey and installation of windows and external doorsets.
Meeting industry standards
When specifying wooden windows, whether for a new build or replacement like-for-like check that they meet acoustic standards – including BS EN ISO 140-3: 1995, BS 2750: Part 3 and BS EN ISO 717-1: 1997
If you are looking to renovate a historic property that is listed, or located within a Conservation Area, double-glazing if often a debatable issue. This doesn’t necessarily mean that replacement wooden windows will provide poor acoustic performance because options to be considered include narrow glazing units and laminates. Some conservationists still champion the installation of secondary glazing, which is a fully independent window system installed to the room side of existing windows. Secondary glazing can provide an excellent reduction in noise, particularly when fitted with acoustic glass but the disadvantages are that it takes up internal space (an air gap measuring at least 100mm is required), users of the building do not like to open two sets of windows and it can prove difficult to keep the glass clean.