Glass Extensions for Listed Properties

Both English Heritage and local authority Conservation Officers will often recommend that 'glass box' extensions are used when extending out from a Listed Building.

A glass addition that is architecturally modern, and has a minimal impact upon the host building, will often be viewed more favourably than a traditional extension or Victorian style conservatory. A glass box style extension makes a clear distinction between the old and new.

Once acclimatized to the idea, and having seen the end result, our clients have been delighted with our contemporary additions to their historic homes.

Listed buildings help us acknowledge and understand our shared history. They mark and celebrate a building's special architectural and historic interest, and also bring it under the consideration of the planning system so that some thought will be taken about its future.

Our frameless glass extensions are popular with planners for listed buildings. We are proud that our frameless systems enhance our historical buildings.

Things that planning and conservation officers look for are as follows:

Glass extensions can be constructed in such a way that there is minimal contact with the original building itself. Clever framework that can be attached to the main building by little more than a piece of lead flashing, meaning that the extension is completely freestanding. This is a big plus for conservation authorities as the existing building is left intact and, if the extension were to be removed in the future, there would be little sign of the extension having been present. Furthermore, the extension is an obvious, modern addition to the property and in stark contrast to the original. This is often preferred over a sympathetic or in keeping extension which can blur the lines between the original and extended parts.

MINIMAL INTERFERENCE WITH THE ORIGINAL BUILDING.

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The transparent nature of glass means that this type of extension barely interrupts the view of the original building to which it is attached. Framework can be kept to a minimum and if the building is particularly important, low iron glass can be specified to ensure that any blue or green tint is removed from the glass, therefore increasing its transparency.

UNINTERRUPTED VIEW OF THE ORIGINAL BUILDING.

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One of the main considerations will be what you want to achieve with the extension. Rear extensions are popular to make transitions between indoor and outdoor spaces and often lead off from kitchens at the rear of the house. Side extensions are helpful to make best use of otherwise wasted space. In our experience, if working with a listed building, it is helpful to try to utilise an existing doorway or sash window as an access route to the glass extension. Local authorities tend not to like new openings being created on the external areas of listed properties.

CONSIDER WHERE TO PROPOSE YOUR EXTENSION.

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We have found it extremely beneficial to submit a few options for the conservation and planning authorities to consider at the pre-application stage. Of course, you can state your preferred option but showing some flexibility in the construction, roof shape and overall look of the extension can greatly assist with your chances of approval. If you can get an insight into the thoughts and concerns of the local authority at the pre-application stage, you can be better prepared to answer and deal with the issues in the formal application.

PRE-APPLICATION – BE FLEXIBLE!

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GENERAL BENEFITS AND TIPS FOR A GLASS EXTENSION.

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If you anticipate resistance from neighbours, you may be able to appease them and the authorities with a glass extension as it will have little to no impact on your neighbours 'right to light'. The nature of a glass extension allows light to travel through, therefore not reducing the light to your neighbour's property.

If you require cabinetry in your glass extension and are concerned about the appearance of cabinets against the glass, consider having the glass coated with a block colour of your choice to just above cabinetry level. It will hide the cabinetry and add a design element.

Make sure that the extension that you are proposing is not disproportionate to the overall size of the existing property. This is particularly important with listed buildings or in conservation areas.

Be clear on your energy efficiency ratings. Thermal glass can assist with protecting against heat loss and solar glass against overheating in glass extensions. If your energy efficiency rating is low as a result of a proposed glass extension, consider offsetting with a highly energy efficient boiler.

Check the most recent permitted development rules for your area. Although this will not stop you from requiring permission to extend a listed building, it could mean that planning consent will not be required in addition if your plans meet the criteria