Secondary Glazing - A Conservation Friendly Upgrade

Underlying issues with heritage buildings…

The original windows in heritage buildings and older properties can prove to be very problematic for owners. Many issues must be addressed when speaking about these types of properties, as windows lack insulation, which means that most owners run buildings less efficiently than possible. They enhance noise pollution and attract condensation as moisture builds up, therefore damaging the wood. They are also far more difficult to replace, as conservation rules often prohibit owners from upgrading.

Secondary glazing and its benefits…

One possible solution to all these issues is secondary glazing. Secondary glazing acts as an insulating barrier by creating a sealed air gap between the original glass and the secondary glazing.

There are two main benefits to secondary glazing in particular, which makes this attractive to home owners and property developers. The main benefits include thermal aspects. Secondary glazing creates a sealed air cavity between the original and secondary panes of glass. The air gaps acts as insulation, therefore significantly increasing heat retention in a building.

Another benefit of secondary glazing is the acoustic benefits it provides in terms of noise reduction. As the glass is thicker with two panes present, as well as sealing and the frame design, the noise from the outside reaching the inside of the building is largely reduced.

Examples of successful installation of secondary glazing…

Some examples of secondary glazing being used to correct some of the issues listed above include the Plumstead Library in London. This grade II listed building has single-glazed and metal-framed windows that couldn’t be replaced. As the windows are large and face the high street, there is high external noise and poor insulation. 63 secondary glazing units were fitted. They were well sealed with tight insulation and worked to respect the original appearance of the library.

Insulation was improved by ~1.9W/m2K achieved on the metal-framed windows. As well as this, there was a noise reduction of approximately 45dB.

Another example of this is the Supreme Court building in London. This is also a grade II listed building, where the windows couldn’t be modified; however, as a courtroom, the windows needed to be adjusted to meet the requirements of being a quiet space. To address this issue, all existing windows were secondary glazed and equipped with low-emissivity glass.

In this case, Insulation improved as the U-value decreased to below 2.0W/m2K through the use of low-emissivity glass. There was a noise reduction of more than 45dB as well, achieved through the use of thick laminated glass.

Selectaglaze…

Selectaglaze is a company that specialises in secondary glazing, looking to install additional glazing units to prevent replacing the original windows. They provide services whereby they design, manufacture and install glazing unique to each property’s needs, and they provide a whole range of secondary glazing appropriate to accommodate all property types, with different styles and glass options available.

Secondary Glazing can prove very effective for solving some of the issues that come along with old heritage buildings, and may be something to consider when purchasing a property, as it provides better energy efficiency, comfort and preserves the buildings original style and character.