August 29, 2017

What is the Difference Between a Glass Extension and a Conservatory

Written by Rebecca Clayton

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From aesthetics to planning and practicality, a glass room can often be a better choice than a traditional conservatory.

Glass Room added to a listed property Glass Room added to a listed property

When considering a beautiful glass room, one of the most common questions people ask is how they differ from a standard conservatory. Certainly, there are plenty of similarities; both provide a bridge between indoor and outdoor living, allowing you plenty of natural light while protecting you from the elements. They both act as an extension to your home; a place where you can relax and enjoy the garden view. Apart from that, there are some very notable differences…


Unlike a conservatory, a glass room aims to create a smooth transition to the outside with full glazing, providing unobstructed views. Where conservatories have large clunky frames, a glass room is made of frameless glass panels, giving it a clean minimal look with more light and visibility. Depending on the design, some glass extensions have sliding glass doors or bi folding doors that open completely, transforming home extending the living area. Main Street, a project in Leicester completed by our regional Midlands division, used slim sliding glass doors in a biparting configuration as part of the glass extension design to achieve a fully glazed design in conjunction with the structural glass roof and create an indoor outdoor style of living.

glass extension in Leicetser with sliding glass doors and structural glass roof

Planning Constraints

A conservatory or a glass room is an extension to the house, meaning it requires a building permit and must comply with statutory regulations regarding air-tightness and insulation to ensure it complies with energy efficiency values. However, you can build various single storey extensions without planning permission, providing the extension accords with the following:

  • The extension does not sit forward of the principal elevation.

  • Where it is within 2m of any boundary, the eaves cannot be higher than 3m, and no more than 4m in height otherwise.

  • Rear extensions — no more than 4m in depth (detached house) or 3m in depth (semi-detached or terrace).

  • Side extensions — the width of the extension must not be greater than half the width of the original dwelling.

The South West regional team added a minimal glass extension to this Grade II* Listed manor house in Salisbury, using frameless and slim framed glazing systems in conjunction with timber detailing for a unique design that combines modern and traditional elements. The extension was approved by planning officials due to the expansive use of glass, which helped maintain the original building aesthetic whilst enhancing the functionality.

Grade II* listed building with minimal glass extension


Glass rooms are generally more expensive than a conservatory to construct. However, the quality and durability of the aluminium construction versus uPVC conservatories quite clearly account for the higher price.

Contemporary glass extension Contemporary glass extension


Glass Box Extensions are all designed and made to measure by the millimetre before the frames are constructed and the glazing is cut with laser precision. This means installation is quick and efficient with few errors. Issues commonly faced by conservatory builds, such as tightness gaps and condensed water, are not common issues with glass extensions and glass room installations. When the IQ team designed the glass extension at Yew Tree House, the original building envelope was completely preserved to allow the listed building to maintain its charm. Using frameless architectural glazing and backpainted glass, there was a clear differentiation between old and new elements.

If you would like to find out more about glass rooms and glass extensions, please contact the team at IQ Glass.

Glass extension to a grade II listed house Glass extension to a grade II listed house