Double Glazing for Listed Buildings
26 July 2019
Listed buildings are a headache for owners. Not only are all of your building plans subject to a conservation officer’s approval, but you must also constantly select materials that ‘respect the original character of the building’.
Evidently, windows are one of the most visual signs of a building’s character. They are often the most distinguishable part of a property’s exterior, and are often so distinct you can actually infer the period in which the home was built from the windows.
However, despite this beauty, many original character windows are not only in poor condition but offer terrible energy efficiency. In an era of increasing environmental awareness, it is therefore unsurprising that homeowners and property owners who have listed buildings face a challenge: heritage conservation versus energy conservation.
Historic England Guidelines
Historic England stipulates that a conservation officer must assess the significance of your windows and also that double-glazed units are typically between 22 and 28mm thick, which differs heavily from the traditional glass used in listed buildings that are usually 2-3mm thick. This means that it is often impossible to replace original glass with even slim-profile alternatives, as the frame and glazing bars cannot cope with the thickness and weight of the glazing.
When historic properties do not retain significant glass and can accommodate a double-glazed unit without significant alteration, double glazing may be permitted. It is also permitted when replacing steel windows that can accommodate slim double-glazed units.
However, as many listed buildings have already been altered before they entered into a new owner’s hands, different rules can apply. If the windows have already been altered to a non-historic design, you can install new windows that are of a more sympathetic design that have a positive impact. In such cases, there must be no incidental damage caused to the windows from the works.
It is generally advised that repair is better than replacement, which is why many homeowners opt for secondary glazing instead of going to the trouble of adding double glazing. Secondary glazing means you can install a more energy-efficient solution without replacing the window itself.
It is worth noting that secondary glazing not only improves energy efficiency by 75%, it is also not typically subject to a planning officer’s approval. This makes it preferential when working with a window repair. For heritage double glazed windows, either by adding a second window layer or through a complete window replacement, contact our team.
Features such as stained glass and even the irregularities caused by older glass are often deemed as contributing to the character of historic windows. This means that replacement can be virtually impossible. However, if you’re dealing with a repair or only one element of interest in a window, you can benefit from encapsulation, where the significant feature is encapsulated in a new design. This means you can install a modern window that features your original glass to satisfy the conservation officer. Of course, the modern window must also match the original character of the building, which is why all of our heritage windows are tailor-made to fit the original character of your property.
Matching History With Modern Glazing
At The Heritage Window company, we specifically design and build products that retain and respect the original property of heritage buildings. Whether it is a sash window replacement, an art deco style building or a Georgian or Victorian home, we offer slimline aluminium windows that offer the highest standards of energy efficiency.
For replacement windows, owners must choose materials that respect the original character of a building whilst offering modern benefits. Our conservation range is the perfect choice for steel window replacements, offering a slimline profile and minimalist sight lines.
While you will need to submit your plans to your planning officer and gain their approval, our vast experience in the sector means we can help you design and implement a solution that will satisfy both conservation and energy-efficiency needs. Get in touch today to learn more about double glazing in listed buildings.