sound proofing windows

Sash Window Soundproofing

Acoustic glass and perimeter seals will improve noise insulation but the design of sash windows  prevents perfect sound proofing.

Sash Window Specialist accept that period windows will never be totally sound proof. Although we can’t offer a perfect solution, we do know Where improvements can be made.


soundproofing & sound sealing period windows & Doors | Sash Window Specialist Perth-

Noise leaking into our homes is an ever increasing annoyance. Sash Window Specialist offer advanced solutions to help control noise pollution entering from wooden period windows & doors. 

Sound proofing sash windows, and old buildings in general, is a complicated and imperfect science.  We have worked with  several leading acoustic consultant companies who took before and after noise level readings.  Results have varied from property to property, for the same upgrade specifications.  Although we can not offer a perfect solution, we do know how noticeable improvements can be made.

Acoustic Window Seals

The first step towards improved sound insulation from timber sash windows and doors is to ensure that effective draught seals are fitted and any air gaps around the frames are sealed. No matter how well the glazing reduces noise, if there are air gaps then noise will penetrate your home. Draught seals reduce air leakage from outside so they also reduce air-borne noise & dust.

Sash Weather & Draft Seals.When acoustic sealing is the primary concern, over durability, a Schlegel Q-Lon Weatherseal is available on request.  Q-lon seals offer slightly better acoustic insulation over the pile / brush draught seal that we recommend for sliding windows.  Using this type of sash seal increases friction making the window slightly stiffer to open and the surface of the seal may tear over time.

Many of our customers have commented on how well our Standard Draught Seal & Overhaul service has reduced noise. But in many urban environments this solution is not adequate and upgrading the glass should be the next consideration.

Replacing Window Glass For Sound Proofing

A thicker glass will improve The acoustic insulation and soundproofing performance Of Your Windows.   

Sound proofing for noise reduction is a very complex problem and no matter how good a particular product measures in laboratory tests those results are not always reflected in real world situations. Glazing manufacturers offer their test results as guidance only. 

We offer a wide range of glazing options from all the leading glass suppliers.


Acoustic Properties Of Glass

Obscured / patterned sash glass

Float Glass – the standard glass that has been fitted for many years is often only 2 or 3mm thick. Simply increasing the thickness will reduce the amount of noise. 

When a wide range of decorative glass is required, such as bathrooms, this is the best solution. Patterned glass is available in a range of thicknesses dependent on the design.

Laminated window Glass.Standard Laminated Glass – manufactured by bonding multiple panes of glass together with a thin inter-lay film sandwiched between the glass layers. Laminated glass has many benefits including greatly reduced ultra violet (UV) light ingress, Grade A safety glass, improved security as well as improved noise reduction. Improvements of up to 24% can be achieved over existing 3mm float glazing.  In our experience standard laminated glass often offers a cost effective solution. A limited range of patterns are available.


Accoustic Laminate Window Glass.Smart’ or Acoustic Glass – laminated glass that incorporates a ‘smart’ interlayer. The interlayer is designed to dampen noise and may reduce noise by up to 40% in comparison to similar thickness float glass. Acoustic glass is more expensive than standard laminated glass.

Sound Proofing Period Windows & Doors 2

double glazed unit for sash window.
Double Glazing – standard double glazing with 2 glasses of the same thickness offers little sound insulation. However when laminated glass is incorporated into a sealed double glazed unit the benefits can be significant.  This is not only a great solution for reducing noise but the thermal improvements are a welcome benefit to every home.

Before replacing glass consider:

  • In vertically sliding sash windows the weight of the glass must be offset by the balance mechanism. For every increase in the thickness of glass there is a corresponding increase in the cost to re-balance the mechanism.
  • It is usually possible to double the thickness of single glazing without modification to the frame e.g. existing 3mm glass can be replaced with 6.5mm.
  • For glass thicker than 6.5mm the frame will usually need to be altered. Unless noise intrusion is a very substantial problem the costs incurred to install thicker glass are seldom cost effective. Replacement double glazed laminated sashes are recommended for the best noise reduction.
  • Replacing old glass with new can change the colour of the light entering your home and alter how light reflects from the glass.

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Most effective Sound-proofing For Sash Windows

soundproofing & sound sealing period windows & Doors | acoustic glass | Sash Window Specialist Perth-The voids created for the weights in a traditional box sash window are a weak spot for noise intrusion that can also resonate, amplifying the problem.  On busy main roads the best solution maybe to sacrifice the ability to open the window altogether.  By removing the weights, insulating the voids and sealing the frames shut significant acoustic reduction can be achieved.  When combined with acoustic glass this is the most effective way to soundproof a sash window without secondary glazing.

Secondary Glazing

Draught Proofing Timber Sash Windows| Sash Window Specialist UK & AUSecondary glazing combined with soundproofing the original window is the most effective way to stop noise from a period window.  Aesthetically this may be unacceptable as a second window must be built on the inside of the existing window, with a void between them at least 100mm.   

Windows that are recessed in deep reveals are best suited as they will not protrude into the room.


Noisy Period Homes & Offices

Whilst windows are often targeted as the major cause of noise intrusion they are not the sole culprits. Air vents, walls, floors, ceilings and chimneys are all areas that can be acoustically improved. These areas should all be given equal consideration when an overall significant improvement in noise reduction is expected.

Soft furnishings absorb sound very well. Current trends in hard surface decor, such as removing carpets in favour of polished floor boards or replacing heavy drapes with blinds, only adds to the noise problem. Simply incorporating more soft furnishings will improve problems associated with the noise in your room.