Side Return Glass Extensions: everything you need to know
[Updated July 2025 with new project examples]
Adding a side return extension is one of the best ways to increase and improve the quality of family space in terraced and semi-detached houses. They are extremely popular with our London clients who have outgrown their period homes, but are reluctant to move from a favourite neighbourhood.
What is a side return extension?
A side return extension is typically carried out in the kitchen area at the back of the house. The side return – the pathway that runs alongside the ground floor of your home – makes the perfect space on which to build the extension. Hence the name, ‘side return extension’.
A side extension finished with glass roof panels and glass walling, sliding or bifold doors, offers a bigger kitchen and a brighter, lighter, open-plan living space.
Glazed side return extensions bring welcome natural daylight with no loss of privacy
What type of structure works best for terraced home extensions?
Our recommendation is to choose an all-glass insulated or thermally broken aluminium frame extension. In the glazing industry, these are sometimes called Wintergardens. They are robust, high-performance structures with slim sightlines.
A glass extension with a large fixed picture window and window seat is a huge success for this London home
Is a solid roof or a glass roof best for a glass extension?
A structural glass roof with a fixed or opening roof light is a great option for your extension. There are several models available that automatically open and close according to the temperature to ensure a perfectly ventilated space.
A Hampstead home extension has huge glass panels, clarestory windows and fixed rooflights
Does a glass extension need solar control glass?
Advanced solar control coatings on glass panels reduce the amount of UV rays entering your extended living space, adding both comfort and peace of mind about potential fade damage to your furnishings. For a more detailed explanation, read our quick guide to solar control.
Are folding doors or sliding doors best for a kitchen extension?
Sliding doors work best for glass extensions with wider openings to the outside. There is room for one or more of the panes of glass to slide behind another. And with more room, having a fixed panel makes less of a difference.
Bifold doors work very well for smaller extensions, as they allow for the glazed panels to be opened in a concertina motion. Bifolds run on one track, whereas the sliding doors will always have at least two. With different aesthetics and final look, the choice of sliding or bifolds for your extension does come down to individual preference.
Tim Hedges, Managing Director of ODC Glass for 15 years, explains:
“As a rule, we find that where the opening to the outside space is not particularly large, our customers tend to choose bifold, or folding doors, as this means that they benefit from being able to have the whole space open to the garden. Where the opening is larger, we are seeing more people opt for sliding doors as, for them, it matters less that one-third, or perhaps even half the space, will still be a glass panel.
Sliding doors will have a much less visible profile when closed, which some customers think adds more ‘wow factor’. For example, we have just completed an installation of sliding doors where our client’s house has a stunning view onto Poole Harbour. The choice of sliding doors in this case was absolutely the right one. In terms of visuals, both options look great, but many customers still prefer the minimal look of a well-designed pair of sliding doors.”
Does a side return extension for a terraced home require much structural work?
Typically, major works needed for this kind of extension include building a new wall on the boundary between your land and your neighbour’s, on the kitchen side. This will require consultation with the owner of your neighbouring property. The wall might have to be installed solely on your side. The other major structural step is to knock through the existing sidewall of the rear room.
Is planning permission needed for a terraced home glass side return extension?
Council rules for glass extensions changed back in 2008, so from 2017, planning permission is no longer required. This applies as long as the extension is only on the ground floor and is no higher than four metres.
An extension can’t be any wider than half the width of your house before the build starts. It’s worth noting that even though you might not need planning permission, there will be building regulations to comply with.
How long does it usually take to install a side return extension?
For a fairly standard project, it takes somewhere between eight and ten weeks for the structural work. Deciding on glazing specification and manufacturer should be one of the first tasks of any project planning to ensure windows and doors are ready for installation when the openings have been created.
Our top tip for a successful glass extension
Tim advises, “It’s key to plan the glazing elements of your project early. High-quality glazing is a considerable investment and you have to get it right.”
One of our favourite Side Return Extensions for a London terraced home
A perfect example of how a glass side return extension creates a connection with the outside. It spans the width of the house and its narrow garden, and features a floor-to-ceiling wall of glass and a structural glass roof. It’s now a spacious family-kitchen-dining room, with lots of light and views to an inviting, relaxed garden.
Looking for more terraced home extension inspiration?
Explore glass extensions designed for previous customers on our Projects Page, including a delightful glass extension for a London terraced house
Why not work with a professional experienced team who know what it takes to achieve great results? Read more about the ODC team here and if you’d like any guidance on glazing design for your project, please give us a call on 03300 586 792 or complete our contact form today. We’ll be delighted to help.
