Glass in Listed Buildings

Architectural Glazing is a highly successful building material when renovating or updating a listed or heritage building. Highly contemporary, fully glazed extensions or glass additions to listed buildings are often preferred by planning officials and bodies such as English Heritage as the contrast between the modern glass and original building very easily defines what is new and what is old.

Also, glazed elements are sometimes the preferred additional material to heritage spaces as the glass is naturally transparent and therefore does not block the view of or alter the original design of the protected building.

Once glass has been decided as the building material of choice for your listed building renovation the next step is to ensure that the glass does what is required; serving whatever function is required for the design and building specification whilst causing minimal disruption to the original structure.


Clear Frameless Glass

Where glass structures on listed buildings are required to be as minimal as possible the use of structural glazing is the best tool. Structural glass is a bespoke architectural glazing technique that utilises the inherent strength of glass to create frameless installations of glass. On listed buildings, structural glazing can be used to create

The fact that the glass is frameless means that the new addition to the building will have very little impact on the overall appearance of the building, which is often the requirement for additions to listed buildings.

The connection between the structural glass and the listed building is important and should be designed individually for each listed property by the glazier. The structural glass fixings need to be minimal but also need to be fixed to the listed structure in a way that maintains the integrity of the building fabric.

Glass for Historic Building
Yew Tree House Architectural Glazing

Specialist Glass Technology

For a clearer finish to your glass installation Low Iron glass can also be used with great effect on listed buildings. This specially processed glass has a much better clarity than standard toughened glass as it has a lower iron content to reduce the amount of green tint that naturally occurs in glass. This obviously creates a clearer barrier on the glass elevation or installation.

Low Iron Glass can be especially useful in structural glass installations which use thicker glass specifications than framed solutions. When thicker glass compositions are used the green tint in normal 'clear' glass can be more noticeable. Specifying Low Iron Glass for these structural elements will reduce the green tint within the glass makeup and result in a clearer structural glass install for the listed building.

It is important to keep in mind that Low Iron Glass may not always be necessary for your glass specification, especially if the glass unit includes any coatings (such as low e or solar control). The team at IQ will be able to advise you as to whether Low Iron Glass will be a useful investment for your glazing package and offer technical data on the light transmission and G factor of your glass specification.

Anti-reflective glass is another useful tool for listed building renovations. The glass goes through a specialist finishing process to reduce internal and external reflection from the glass panel resulting in a glass unit that is almost invisible. This solution is particularly effective when the glass is being used as a barrier between spaces, such as glass extensions, links or to block-in existing openings. These create nearly invisible structures from afar to maintain the integrity of the original building.



Heritage Glazing Systems

Instead of creating a contrast between old and new with your glazing, sometimes it is required to create a heritage design for new glass installations on a listed building. This can be done using various Heritage Glazing systems depending on the planning requirement from the listed building consent.

Mondrian® Glazing 

The Mondrian® Glazing systems are a collection of artisan steel windows and doors that beautifully replicate the traditional industrial or loft-style windows on many listed properties. The range includes non-thermally broken solutions that exactly match the design of traditional steel windows and use the same profile as many well-known traditional steel systems.

If you are looking for improved performance for your heritage glazing you can use one of the Mondrian® thermally broken systems. These steel windows and doors offer the same steel design as traditional glazing but with an integral thermal break for enhanced thermal insulation. They can be fabricated using traditional steel, stainless steel, Corten steel or architectural bronze.

Sieger Legacy

If you are able to use an aluminium profile for your heritage glazing design then the Sieger Legacy collection is your first choice. The range of thermally broken aluminium windows and doors offer a traditional design to the profiles with slim sightlines. This replicates the appearance of a steel system without the additional costs of working with steel. As the aluminium frames can be powder coated any RAL colour (or a selection of specialist finishes) you can ensure the installation exactly matches the heritage design.


steel look windows to london mews house
steel windows and doors
georgian style windows to listed hotel
structural glass detail

The Glazing Design + Install

When altering or refurbishing listed or heritage buildings ensuring that no damage is inflicted upon the listed building is another large consideration to make.

IQ use specialist surveying and fixing techniques to ensure that all our pre-bonded angles are perfectly positioned with the listed buildings mortar joints. Using the latest in surveying technology, IQ’s surveyor can create a 3D model of the opening and all brick or stone joints in CAD, giving IQ an accurate vector model of the building on which we will be working. This enables our experienced designers and fixers to install glass panels without damaging the brickwork of listed buildings.

All finishing to listed buildings must be detailed and intricate in order to maintain the honour of the original work. All design details must be created individually for each project to ensure that the design and detailing is correct and applicable to each application.

Above all else you must ensure your architectural glazier has lots of experience in working on listed buildings. You can see a selected list of some of IQ's past listed building projects below.



Reference Projects

Here are is a curated list of previous listed building projects that IQ have been a part of:

Residential Projects 

Ashford Mill - replacement glazing to listed mill

Ansty Manor - glass extension and link to listed house

The Garden Room House - glass extension to listed house

Yew Tree House - glass extension to listed cottage

Cotswolds - award winning extension to listed cottage

Commercial Projects

Warwick Hall - award winning renovation to listed church

Gravetye Manor - a glass extension to a listed hotel

Blenheim Palace - glass infills to the archways of the World Heritage Site

Wellington College - various elements structural glazing to the listed school

Somerset House - various structural glass installations to the historical building

Chicheley Hall - a glass extension to a listed building

Tower Vaults - a glass extension to a listed building

Treacle Factory - replacement glazing to a listed building

Portsmouth Grammar School - glass infills to a listed school

The Grove - replacement glazing to a listed hotel

The Odney Club - glass link for listed manor house





glass extension to listed hotel
extension to listed cottage
Dan Borthwick
Commercial Manager
Dan is the commercial manager for the aluminium division of IQ. He has extensive knowledge of aluminium systems and their fabrication as well as the technical aspects of window and door specification. Based at the IQ head offices in Amersham, Dan spends his time meeting with architects and other building professionals to help create glazing specifications for projects and ensure glazing packages are in budget.
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