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Glass side extensions for terraced homes: FAQs

17 February 2021
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Adding a side return extension is one of the best ways of increasing and improving the quality of family space in terraced and semi-detached houses. Here are FAQs to help you make that next step towards transforming your home.

WHAT is a side return extension?

A side return extension is typically carried out in the kitchen area. 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 extensions. Enjoy a bigger kitchen, as well as a brighter ground floor open plan living space.

Glazed side return extension
A glazed side return extension brings welcome natural daylight with no loss of privacy
WHat type of structure WORKS BEST?

Our recommendation is to go for an all-glass thermally broken (insulated) aluminium frame extension. In the industry these are often called Wintergardens. They are robust, high performance structures with slim sight lines.

Side return extension with bifold doors
A side return extension with bifold doors and a flush threshold maximise access to the outdoors 

An opening roof light is a great option for the roof panels, too. There are a number of models available that’ll automatically open and close according to the temperature, so you can ensure you’ll always have a breezy, airy space.

It’s also worth remembering to include some fixed panes in your design, simply so you can enjoy the uninterrupted views of your garden when it gets colder.

Consider advanced glazing options such as solar control – this reduces the amount of UV rays entering your extended living space, adding both comfort and peace of mind about potential fade damage to your furnishings.

Are FOLDING or SLIDING DOORS best for an extension?

Folding and sliding doors both have their unique benefits.

Bifold doors for modern kitchen
A single traffic door allows easy access to the garden on days when it’s too cool to fully open bifold doors

Sliding doors open by sliding one or more of the panes of glass behind another. Bifold (or folding sliding doors, as they’re otherwise known) open in a concertina motion in which the panels fold together. Bifold doors can run on one track, whereas the sliding doors will always have at least two. This won’t bother everyone, but it does affect the aesthetic and final look.

The choice between the two is often a matter of how large the opening to the outside space is. If the opening is very wide, sliding doors tend to work better. With more room, having a fixed panel makes less of a difference. Bifold doors, meanwhile, work very well for smaller spaces, as they allow for nearly the whole set of panes to be opened up in summer months.

Managing Director of ODC Door & Glass Systems Tim Hedges 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 than one-third, or perhaps even half the space, will still be a glass panel.

Sliding doors will have much less visible profile (or frame) when closed, which some customers believe aesthetically adds more ‘wow factor’. For example, we have just finished 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 ‘wow’ factor that comes with a good pair of sliding doors.”


There are a few major works needed for this kind of extension including:
– Build 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.
– Add a new roof to the extension area. Many people go with a fully glazed roof or a skylight in order to create a brighter kitchen.
– Knock through the sidewall of the current rear room.
– Install a new floor to integrate the existing and new extended area.

side return extension with roof glazing and bifold doors
A completed project reveals how a seamless side extension delivers light and space

Council rules for this kind of project actually changed back in 2008, so as from 2017 planning permission is not required. This applies as long as the extension is only on the ground floor and doesn’t go any higher than four metres.

It also can’t be any wider than half the width of your house’s size before the build starts. It’s worth noting that even though it’s fairly likely you won’t need planning permission, there will be building regulations you’ll need to comply with.

It’s important to consult with your project manager and contractor on these issues.


For a fairly standard project, it’ll tend to take somewhere between eight and ten weeks for the structural work. Plus, of course, the time for finishing and decorating the new interior.

If you’re embarking on a home extension project, Tim advises:

“It is 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 the keys to creating a successful side return extension is to work with a professional experienced team who know what it takes to achieve great results.

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 are happy to help.