Glazing for Listed Commercial Buildings
A guide to the best glazing systems for listed commercial buildings.
A listed building is any building that is protected for the national interest because of an architectural or historical significance. The older a building is and the more unique it is, the more likely to be listed it is.
The Listed Status prevents any changes or alterations being made to the building without consent from the planning system, which is less likely to be given for buildings of historic significance. There are different grades that listed buildings are identified by in the UK, as the historical significance can vary so greatly.
UK Listed Building grades:
- Grade I: only 3% of all listed buildings are identified as Grade I and these tend to be old buildings of outstanding and special interest.
- Grade II*: this grading accounts for approximately 5% of all listed buildings and is applied to buildings with significant interest, but not as much special interest as Grade I.
- Grade II: these buildings have less significance and special interest than the previous two grades, with fewer restrictions and a higher chance of being approved for changes.
Many listed buildings feature historical window systems, which were typically delicate and very fragile, formerly used as a symbol of wealth for rich landowners. Although these windows do not offer modern performance values, they do have a specific appearance that is considered to be historic. When changing or renovating a listed building, the aim of the planning application process is not to prevent any changes from being made but instead to preserve any historic or special value. Most of the time, changes to listed buildings must be in keeping with the age and aesthetic of the wider building envelope.
Structural glazing is often preferred for historical or heritage buildings, due to the subtle and transparent nature of frameless glass. English Heritage are amongst the organisations that favour architectural glazing for buildings of this nature, as this modern glazing solution created a clear differentiation between old and new elements, allowing the original buildings to retain the original design and charm.
The dedicated IQ South West regional division are currently on-site at Exeter cathedral, installing frameless glass arches and frameless glass doors to create an entrance design that protects the area from draughts. The sensitively designed single glazing is extremely subtle in design, with a solid wood structure to enhance the traditional aesthetic inside the Grade I listed building.
Our Invisio structural glazing system has been designed in house to offer architects and specifiers completely frameless glass solutions that have very few limitations.
Full glass box extensions can be designed for listed buildings, with a very minimal design to enhance the surroundings. Gravetye Manor, a Grade II Listed hotel, benefitted from a large glass box extension when they renovated and extended the Michelin star restaurant, complete with slim sliding glass doors that were in keeping with the subtle design.
The extension was sensitively designed to enhance the traditional manor house, combining modern glazing with traditional architecture for a unique finish.
When working on listed buildings, IQ can engineer bespoke fixing details to ensure original structures remain completely preserved at all times. 3D laser surveys can be carried out to undergo extremely detailed designs, like at Blenheim Palace where frameless glass arched doors were installed in the heritage archways. To preserve the original stonework, a laser survey allowed IQ to avoid the stones completely, instead of fixing the hinges into the mortar joints.
For the clearest glass appearance, low iron glass can be specified. This will eliminate the green tint that naturally occurs in glass, part6oicuarly on exposed edges in glass beams or fins. Due to the glass having a lower iron content, it has much better clarity than standard glass.
Some glazing installations will not require low iron glass, where other technical glass solutions have been used such as solar control glass, but the technical team at IQ are on hand to assist with glass specification on a project by project basis.
Anti-reflective glass is another solution that is commonly specified on listed building projects, with the glass going through a specialist finishing process to eliminate any reflective properties for the most subtle finish.
Steel framed glazing can be used to maintain a traditional design, with modern glazing technologies allowing these slim systems to deliver excellent thermal performance.
To replicate traditional steel windows, Mondrian steel windows can be specified in a range of bespoke arrangements with fixed and opening elements to suit any commercial building design.
Steel framed windows were used at Snelsmore House, a traditional barn style wedding venue. In conjunction with the steel windows and doors, aluminium glazing systems were specified with a glazing bar design for a steel look.
Aluminium can be used to create steel look glazing without the price tag and limitations, as it has lightweight properties that can offer a more flexible design. The aluminium doors at Snelsmore House were triple glazed and oversized, something that would have made them unreasonably heavy if they had been true steel.
Many of our premium aluminium systems can be specified with glazing bars, but the Sieger Legacy system has been specifically designed to offer a steel look. Many of the newer aluminium systems have deeper frames than traditional steel glazing, but our Legacy systems utilise ultra-slim, thermally broken profiles to mimic steel.
It is important that your chosen glazier, along with anyone else working on the project, takes extra care throughout the installation and site visits to ensure the listed building is not damaged. There are a number of specialised surveying and fixing techniques that IQ use to ensure that all pre-bonded angles on the project are positioned precisely within the mortar joints.
Where required, our surveyor creates a 3D model of the opening we are installing into, complete with all stone, brick and joints to produce an accurate vector model of the building. IQ’s proven knowledge and experience working on listed buildings makes us the right glazier to take on projects of a complex nature.