Side return extension cost guide 2023

If you need some extra space in your home but you don’t want to eat into your garden, have you considered a side return extension? If you live in a terraced house or another type of property that has a small amount of space at the side that goes widely unused, this type of extension could be the perfect answer for you. But how much does it cost?

The average cost of a side return extension is £46,000 excluding VAT. Expect it to take anywhere up to 4 months to complete, assuming you have any planning or party wall applications agreed already. But the size of the extension, what you want to use the extension for and the complexity of the job will impact the final cost. Make sure you get a range of quotes from different size companies to ensure you’re getting a fair price for your side return extension.

What is a side return extension?

A side return extension makes use of the space that you commonly see at the side of terraced and semi-detached houses. They’re small alleys that people often use for storing bikes and bins, but otherwise go unused - so it’s the perfect way to add space to your home without eating into your garden.

Often, side return extensions are the ideal solution to making your kitchen bigger, but that means knocking through the external supporting wall, which will increase the cost. Some people opt to have the side return extension added to the outside wall, making it more like a lean-to conservatory.

Will I need building planning permission?

Usually, you won’t need planning permission for a side return extension as it falls under permitted development rights. There are a few criteria that your side return extension needs to meet to be within permitted development rights:

• It must not exceed more than 4 metres high
• It must be single storey
• It must be no more than half the width of the original house

It’s also worth bearing in mind how much your property has been extended in the past. You may only extend up to half of the area around the original house.

Conservation areas

Another thing to watch out for is whether you live in a conservation area. If you do, you’ll need to apply for planning permission. Since side return extensions are common in Victorian terraced houses, there’s a higher chance that your home is in a conservation area. Make sure you do research into this before engaging any tradespeople.

Party Wall Act

You’ll also need to consider the Party Wall Act. This is a piece of legislation that requires that you notify your adjoining neighbour of any ‘notifiable’ works that you wish to undertake. The adjoining neighbour may then consent or dissent to the notice. It’s worth speaking to your neighbours about your side return extension, well in advance of serving any notices, so they know what to expect.

Uses for your side return extension

Kitchen

The most common use for side return extensions is to make the kitchen larger. Lots of terraced houses have narrow galley kitchens and even a narrow side return extension can make the kitchen feel much larger and make it easier to move around in.

Lots of people opt to have high ceilings and roof lights in the extension to improve the light and general feel of the kitchen. People that have the room for a larger side return kitchen extension may also opt to turn it into a kitchen diner to make use of the space.

Shower room

Homes with one bathroom may use their side return extension to add an extra shower room to the property. Bathroom designers are used to maximising space in their designs, so speak to one to see what they suggest for adding a shower room into your side return extension.

Cost breakdown for a side return extension

Although a relatively small type of extension, there is still a lot to think about when it comes to building a side return extension. Here’s a breakdown of the costs involved and the percentage you can expect to spend on each area:

Cost breakdown of a side return extension as a percentage

Area	Percentage of budget
Architect	4%
Admin fees	1%
Structural engineers	3%
Surveyors	2%
Tradespeople	30%
Materials	20%
Fittings	5%
Glazing	15%
VAT	20%

If an average side return extension costs £46,000 excluding VAT, you should expect to spend around £18,500 on admin fees, fittings and materials. Labour and service costs will vary depending on your location, with London seeing the highest prices.

Is it worth building a side return extension?

Some people wonder whether it’s worth building a side return extension, especially if it’s narrow. The main thing to consider is how much value it will add to your life - and to the property itself.

Side return extensions give you more room without sacrificing garden space, and will often improve the indoor-outdoor connection of your property. These benefits will add value to your property as buyers look for homes that have made the best use of the space available, rather than taking the most expensive option.

Although side return extensions are often small, they can improve the quality of your life in your home by much more than you think. Adding that extra bit of space to your kitchen to allow you to move around more freely or reducing bathroom queues in the morning can make a huge impact on your family’s wellbeing. It might even mean that you decide to stay in your home longer than you originally planned, which makes it even more cost-effective.

Get competitive quotes from builders near you

There are lots of different costs involved in a side return extension, so make sure you get a range of quotes from builders, architects and structural engineers to get an accurate representation of how much a side return extension will set you back.

Post a job on HaMuch to get quotes from reputable builders in your area.

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