Ideas and inspiration for house extensions
Thinking of transforming your home with an extension? We guide you through costs, planning rules, design ideas, and how to get a quote.
Pearcroft Road, Waltham Forest
Ground floor and loft extensions
Millington Road, Cambridge
Ground floor and two storey extensions
Brassey Road, Winchester
Ground floor extension
Kingsbridge Road, Merton
Ground floor extension
Benhurst Gardens, Croydon
Ground floor extension
Kellerton Road, Lewisham
Ground floor extension
Alexandra Road, Merton
Loft and ground floor extensions
Christchurch Lane, Lichfield
Loft and ground floor extensions
Beverley Close, Epsom and Ewell
Ground floor extension
Grampian Gardens, Barnet
Ground floor extension
Walm Lane, Brent
extensions
Badgers, Epping Forest
Ground floor extensionWhat is a house extension?
What is a house extension?
A house extension is when you expand your home by adding new space, whether that’s a bigger kitchen, extra bedroom, or even a whole new floor. It’s one of the most effective ways to create room that works for your lifestyle, while also boosting the value of your property. With moving costs high and the stress that comes with it even higher, the idea of expanding the space you’ve already got appeals to lots of people.
What are the different types of house extensions?
House extensions come in many different forms, including side extensions, loft extensions, front extensions and more. Whichever one you choose will depend on what works for your house. Let’s take a look at some of the most popular:
Rear extension
Built onto the back of your home to extend into the garden, a rear extension is perfect for creating a bright, open-plan space.
Side-return extension
This makes smart use of the often-wasted passage running alongside the ground floor of a property, usually in terraced houses. A side-return extension fills that space to add more square footage without sacrificing any garden.
Wraparound extension
This combines a side and rear extension, adding an L-shaped space. Ideal for period homes, it creates a larger, more flexible living space by wrapping two sides of an existing property.
Two-storey extension
Also known as a double-storey extension, this involves building up as well as out, doubling your space within one footprint. It’s efficient, and often adds significant value with the addition of more rooms upstairs as well as downstairs.
Example house extensions with build costs
How much does a house extension cost in 2025?
There are so many factors that contribute to the cost of a house extension. The type of extension you’re doing, how big it is, the materials you want to use, and where you live all play a role. But as a rough guide, the cost of an extension in 2025 is somewhere between £2,200-£3,500 per m² (without VAT). If you live in London or the surrounding areas, it’ll more likely be in the upper end of that range.
Do you need planning permission for a house extension?
Do you need planning permission for a house extension?
Not every house extension needs planning permission. Some can be done with permitted development rights instead, which can enable you to extend to a bigger footprint than you might with planning permission. The rules for permitted developments are quite complicated, though, so it’s a good idea to work with an architect to understand what you can and can’t do. For example, a single-storey extension will only be a permitted development if it doesn’t extend more than 4m from a detached house, or 3m from any other type of house. There are separate rules for loft conversions, garage conversions, and other types of extensions. And don’t forget that some homes have had permitted development rights removed completely, while others have very restricted rights. It all depends on a number of factors, including location, the era it was built in, and the type of property it is. Resi’s experts can help you figure out whether your project needs planning permission in a free consultation call.
0 House extensions recently submitted for planning in the UK
How can I finance my extension?
How can I finance my extension?
One of the biggest considerations that goes into a house extension is working out how to finance it. The Resi Finance team can help guide you to the right option, but there are three main routes: Personal savings If you have a big enough fund, using your own savings is a simple, interest-free, and stress-free option. Just make sure you remember the inflation in costs that could arise while you save. Unsecured personal loan A good choice for smaller extensions that cost less. These come with no setup fees, but higher interest rates mean you’ll need to repay your loan quickly, leading to high monthly repayment bills. Remortgaging (or a ‘further advance’) Best for larger projects costing more than £30,000 (which most house extensions will be), this option involves cashing in some of the equity you’ve built up in your home. Remortgaging can offer lower long-term rates than a personal loan, but it all depends on interest rates at the time of remortgaging.
Why choose Resi for your house extension?
Why choose Resi for your house extension?
At Resi, we make home extensions easy. We work with you on design, help you figure out your financing options, handle all things planning, and make sure you stick to building regulations. For no extra charge, we can even introduce you to vetted, local building contractors and help you compare their quotes. We’ve worked on thousands of home renovation projects before, so there’s no question too silly, and no extension is too complicated. If you’re ready to unlock your home's potential, book a free advice call with Resi today.
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House extension FAQs
How long does a house extension take?
House extensions can vary hugely, which means their timelines can, too. But on average, a house extension in the UK takes between 7 and 12 months from start to finish. That includes the time it takes to work with an architect on design, the planning permission process, getting detailed technical drawings, picking your contractors, and then the build itself.
How much value will an extension add?
As a general estimate, extending your home could increase its value by around 10-15%. Exactly how much it will add depends on factors such as where you live, how much you’ve increased the footprint by, and how you’ve used the new space. Bedrooms often give the biggest boost to house prices, but it’s up to you to decide how the extra space will work best for you. For a better idea of how much value you could add to your house, try Resi’s free extension valuation calculator.
Do I need an architect for my house extension?
There are no rules around whether you need to work with an architect for a home extension, but it’s always advisable to work with one. Architects can help with design, planning, and navigating building regulations, saving you time, money, and potentially expensive mistakes.
Can I live in my house during the build?
It’s a personal choice whether you stay in your house during an extension build, or whether you move out. Often, it comes down to budget. If you can afford to stay elsewhere while the extension is done, many choose to, if for no other reason than to escape all the dust! But that’s not always an option. So if the building work isn’t too intrusive, it might be possible to stay (just don’t forget to buy some dust sheets).
Customer reviews
Read more about house extensions
The types of house extensions: design and ideas
A guide to extensions in Conservation Areas
What's the best way of financing a house extension?
House extension cost: how to budget for your project
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Get answers to your pressing extension questions like whether you need planning permission and how much it might cost.
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