Why Secondary Glazing Is Sound

Secondary glazed windows remain a genuine option for property owners in the South of England, particularly for those home owners who have bought a listed building or live in a conservation area, as well as for those whose dwelling is located next to a busy noisy road.

Secondary glazing is not limited to houses that have restrictions, as many a householder or tenant has benefited from the real thermal and sound insulation improvements that occur when secondary glazing is fitted.

I hear you ask, “What is secondary glazing”? The bottom line is that most secondary glazing is basically one pane of glass (or occasionally two panes of glass) held within a frame, which is usually made of aluminium. This secondary glazed window frame is then fitted on the inside of an existing exterior window, usually into the existing window reveal, then it is trimmed and sealed all round.

Secondary glazing is available in several different styles and single and double glazed aluminium profiles such as horizontal sliding and vertical sliding. One can also get single glazed secondary glazing as side-hinged; lift-out and fixed. For optimal sound reduction performance secondary glazing should be installed 100mm from the inside of the external window. Yes, this does mean that you will lose a significant amount of window cill display space, but in return you gain the best possible sound reduction.

Whatever you do, don’t let anyone deceive you into thinking secondary glazing will act as sound proofing, as frankly it won’t, as sound can travel through plenty of other items into a room such as pipework, gaps beneath skirting, air bricks in the walls, and even through walls themselves when they have not been filled with foam insulation. Secondary glazed windows are good value for money as an extremely effective means of sound reduction, assuming of course they are professionally installed.

Replacement double glazing and even triple glazing also assist in sound reduction, and it is true that triple glazing offers more sound reduction than double glazing, as it has a third pane of glass that sound has to travel through, but again don’t be fooled by slick salesmen, as the improvement in sound insulation between double glazing and triple glazing is only about 2 decibels, not enough audible  difference for you to notice.

If it is not possible to fit modern thermally broken replacement double glazing to your property, secondary glazing can makes a decent difference thermally, especially if your home only has single glazing. Even if your swelling has double glazing, secondary glazing will help reduce your energy bills, as it will help retain the warmth generated by your heating system.

Horizontal Sliding Secondary Glazing
Horizontal Sliding Secondary Glazing

Secondary glazed windows also add a 2nd level of security, especially if 4mm or even 6mm thick toughened safety glass is installed. You also have the option of going so far as to specify more expensive 6.4mm laminate glass, as not only is this glass hard to break through, it further reduces the amount of external sound that travels through external glass panes due to the simple fact that it is thicker than conventional glass in domestic windows (usually 4mm wide) .

Make sure your installer mirrors the sections of the horizontal or vertical secondary windows with your existing exterior windows, so that when you look in from the outside you cannot tell that secondary glazing has been fitted. Unlike external double or triple glazing secured into your brickwork or render, secondary glazed windows are far easier to remove if required, with all that is needed is then re-decorating.

There are many different designs of secondary glazing including slim aluminium frames that can be screwed directly into the inside of the external window frames. Whilst these thinner secondary glazed windows are the least cost option, such frames don’t have a sub-frame, so are the least effective both thermally and from a sound reduction point of view.

So before having secondary glazing professionally fitted, make sure you choose the right sort of secondary glazed windows for each room in question, remembering to ensure that the designs you choose will give you access to the external glass so you can clean it or open any external vents. Having secondary glazing installed is therefore a sound decision if you want to benefit from the amount of sound reduction and energy saving it will deliver.


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