How much does a glass extension cost?

How to achieve a high-end architectural glass extension on a budget

While a conservatory can be a relatively inexpensive alternative to an attractive solid glass extension, an engineered architectural glass extension will almost certainly be more costly. However, choosing the right way to open up and add space is a significant decision. A glass house extension offers a sleek, modern solution that goes beyond traditional extensions. But one critical question remains: How much does a glass extension cost?

Our comprehensive guide will look at the different glass extension types, typology etc. enabling designers and contractors to cost engineer their glazing projects.

Fees would need to include the hire of an architect or designer and structural engineer, as more technical design work will be involved. We would advise a minimum budget of £3,000 per m² for the glazing. At IQ, the costs of a glass extension ranges from £30k to £300k.

Factors that affect the cost of a glass extension

Several key factors can affect the total cost of a glass extension.

1. Size of the Glass Extension

The size of your extension is the most significant factor in determining costs. The more glass required, the higher the price. Large spaces require more architectural glass and expertise to ensure safe and precise installation.

2. Style and Design

Whether you specify a full glass extension or a side return extension, the style of the glass extension will impact the cost. Larger, more intricate designs often require bespoke oversized glazing, which will invariably increase the price. Our technical team consider buildabilty from the start, consulting with architects early on in the design process, helping balance design with cost-efficiency.

3. Glazing Options

Choosing the right glazing for your project is crucial. Our high-performance glazing systems are enginneered according to specification adhering with stringent Building Regulations while offering comfort and thermal performance.

4. Accessibility

Ease of access to the installation site can significantly impact costs. Glass panels are large and heavy, so additional machinery, such as cranes, may be required to transport the materials. IQ is skilled in managing challenging installation scenarios on sloping sites or marine environments, but additional equipment can add to the overall costs.

5. Planning Permission and Building Regulation

Listed Buildings often require additional approval. Planning officers typically favour glass extensions due to their discreet and aesthetically pleasing nature.

Planning-related costs may include:

Building Regulations application: up to £300
Building inspections: up to £650
Planning applications: up to £250

For a £30k + budget

Green Barn | Linking old with new with a modern glass link extension | The cost of this glass extension came in approximately £30k.

The cost of the glass link extension was relatively small as the design shape and size was simple.

The property is located within the green belt. Due to restrictions planning permission was granted for an annexe building, the architects proceeded to create a single storey glass link extension to the house. The buildings either side of the link are of brick, timber and weatherboarding, so the glazed extension adds contemporary detail to the farm-like buildings. Wood framing ties the glazed structure to the oak details of the main property.

For a £40k budget

Turney Road | Glass extension using slim framed sliding glass doors, structural glass and frameless roof lights
| All Glazing and Installation costing approximately £40k.

The family that owns this London home asked for a rear frameless glass extension with high thermal performance. A solid roof provided the extension with privacy and solar control glass whilst the slim-framed sliding access doors were positioned around all sides to create a more frameless appearance, wrapping around the new extension. The glazed extension was planned as a living and seating area to the rear of the house and connecting the small garden with the living space.

For a £50k budget

No.10 | Achieve your dream glass extension in your budget | All Glazing and Installation cost approximatrely £50k on this glass extension.

This glass extension design incorporates a new kitchen and dining room facing directly onto the garden. The slim framed sliding glass doors and structural glazing floods the new space with natural light, and the dream indoor-outdoor living experience. To gain that extra ceiling height, fixed and frameless clerestory windows were made from structural glass and installed above the sliding glass doors.

The highly glazed extension provided an intimate new courtyard and an impressive garden dining space.

If you haven’t set your budget …

Shenfield Mill | No Budget? Then perhaps some inspiration from a flawless glass extension in Berkshire | All Glazing and Installation. The glass extension cost in excess of £200k.

This contemporary glass extension in Berkshire features a floating roof using a mixture of; slim framed sliding glass doors, structural glass and frameless roof lights. The bespoke design features a cantilevered roof design with our automated sliding glass doors opening away from a frameless corner beneath, creating the appearance of a floating corner roof design.

The sliding doors here were triple glazed for improved thermal insulation and acoustic performance. Due to the large size and ultimate weight of the doors the whole glass facade is automated, allowing the extension walls to slide back at the touch of a button.

Planning permission for glass extensions

Planners like glass extensions to bridge connections between architectural styles, or to add a very dominant style to the pre-existing home. Conservation officers also like the visible difference between traditional architecture and modern glass. As long as it’s a considered extension, and not at the front of the property, then getting planning permission for your glass extension will be no different to getting planning for a regular extension.

Do keep in mind that you are likely to require an architect or designer to finalise the details of your project. Planning applications for projects with an architect are much more likely to be approved than those without.

If you want any more advice on glass extensions or what you can achieve with your glazing budget then simply make an appointment to visit the Sky House Design Centre which houses the showroom for IQ Glass and associated companies.

For further information or a quotation please call the team on 01494 722 880 or email hello@iqglassuk.com.

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