Double Glazing in Listed Buildings

In this article, I will look to untangle some confusion surrounding what is possible and what is not regarding double-glazing in listed buildings.

Heritage Planning can often throw up difficult scenarios. With the help of an experienced heritage planning specialist though you may be surprised at what is possible.

I have experience working on heritage projects, and success has come from understanding and following national policy and guidance.

The quest to achieve a more economical and environmentally friendly home often leads us to look at upgrading windows on a property. Windows lends so much character to a listed building. Understandably, alterations come under so much scrutiny.

Listed Building Consent

It will be a requirement to obtain Listed Building Consent to add double glazing to a listed building. Applications for listed building consent are submitted to the local planning authority. The local authorities are duty-bound to consider whether the windows in question are ‘features of special interest’ as part of the decision-making process.

It should also be said that the National Policy Framework uses a weighting system where the more important a building’s historic feature is deemed to be, the more scrutiny will be placed on any application to modify that feature.

So if windows are deemed to be the primary feature of the listed building, obtaining consent to modify them will not be easy.

Repair Where Possible

Historic England provides guidance that recommends conservation and repair above replacement when it comes to windows in listed buildings.

One of the difficulties when it comes to upgrading a window to double-glazing from being single-glazed is the size difference. The additional weight and thickness carry a risk of damaging the areas surrounding the windows.

Where this risk is too great, thermal upgrading can be an option. Low-E (low emissivity) coating has been shown in research to reduce heat loss by up to 60%

With that said, double glazing in listed buildings can be possible in the following situations:

• Where a historic window retains no significant glass and can house a double-glazed unit without significant alteration.
• Where replacing steel windows that can accommodate slim double-glazed units.
• Where an existing window can be replaced ‘one for one’. That being it is replaced in a nearly identical fashion and capable of housing a double-glazed unit.

Secondary Glazing Vs Double Glazing

It can be confusing to see these two terms used, and both mean different things.

Secondary Glazing involves installing a supplementary glazing panel on the inside of an existing window.

Double glazing is where two panes of glass with a gap filled with gas between the panes are installed in a single unit. Double glazing is more effective for insulating compared to secondary glazing.

Benefits of Upgrading

The benefits of upgrading the glazing in a listed building include:

• Money Saving and energy efficiency – Upgrading a window can increase it’s heat loss by up to 75%
• Noise Reduction – A good one-for-one double-glazed unit will reduce noise coming into the building.

How can we help?

As an expert in heritage planning, Simple Planning Solutions can help you obtain the listed building consent you may require to install double glazing in your listed building.
Get in touch and I can guide you through your options based on your specific circumstances. Heritage planning situations are complex, and that is where Simple Planning Solutions can step in to provide the help you need.

Thanks for reading.