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How much does a House Extension cost? 2023

Average Price
£1,320 to £2,500 per square meter

How much will I pay for my Property Extension?

Want to create more space but not sure of the dent it will make in your pocket? Read our handy guide to find out how much it will cost to carry out a property extension.

What is a Property Extension?

A property extension involves extending the current boundaries of your home. They come in various shapes and sizes depending on your budget and the amount of extra space you are looking to add. For example, you can add a simple single-storey extension at the back of your home. This would only involve removing a partial wall or demolishing an existing wooden extension in favour of brick.

House extensions can also be far more extensive, especially if building to the side of your home would require the external walls to be demolished and rebuilt. The most expensive property extensions span more than one storey high. Though, these are likely to add the most value to your home especially if extra bedrooms or bathrooms are created. 

How much does a House Extension cost? 

It’s important to consider just how much your property extension project will cost. Based on the prices of local UK professionals, the average cost is given below: 

Minimum cost (per square meter)£1,320
Maximum cost (per square meter)£2,500

On average the total cost is between £15,000 and £100,000 depending on whether it’s a single, double or multi-storey extension.  

 It takes between 6 and 20 weeks to complete a property extension, and labour makes up a large portion of the costs. You may also require various planning certificates or assessments before the work can even begin, which could be as much as £800 each. 

What affects the price of getting a property extension? 

 The cost of a property extension can vary depending on different factors. These include: 

  • Your current property

  • The extension size

  • Single or multi-storey

Your current property

The age and style of your property could determine which type of extension is more suitable. Although getting expert advice does come at a cost, it will ensure the potential of the property is reached. 

As there are so many ways you can go about extending your home, you need to decide what is most important. For example, is it simply a case of wanting a bigger kitchen, or would the upstairs also benefit from an extension too? 

Remember that any extension work you do will make your garden area smaller. You’ll also need to consider any access issues too, especially if you are building out to the side of the property. It’s possible to build a double-storey extension that is hollowed out at the bottom so that you don’t lose access. 

The house extension size

Property extensions come in all shapes and sizes. Remember that your builder will charge per square meter, so the size will be the biggest determiner of the overall cost. If you have a lot of land at the side or rear of your property, then you have the room for a larger extension. But with the added floor space comes an increased cost.

Single or multi-storey house

The most common and cheapest form of a property extension is a single storey one. As the name suggests, it will only be on the ground level of the property. A single-storey extension can be used to add more space to any lower floor room in your house. However, they are usually built to create a larger kitchen or dining space. In bungalows, single-storey extensions can create extra bedrooms.

Double-storey extensions involve both the ground and the first floor. At the top, you can either choose to add a flat roof or extend your current roof space to blend with the look of your property better. Adding a roof will be more expensive, but does give the option for a loft conversion in the future. 

Another option is a multi-storey extension. This will give you additional space on the ground floor, first floor, and the top floor of your home. Multi-storey extensions are the most expensive but will add the most value to your home, especially if additional bedrooms or bathrooms have been created in the process. 

Type of extensionHighest average price (in total) Lowest average price (in total)
Single storey£40,000£15,000
Double storey£60,000£38,000

Single storey extensions are by far the cheapest option, starting at just £15,000 on average. The prices fluctuate because your builder will be working in the square meters you wish to add, rather than the extension type alone. The spec of the build whether it be basic, standard, or deluxe is also going to impact the price. 

Multi-storey extensions are the most expensive, ranging from £47,000 to £100,000 for larger extensions. However, as these will increase the living space on every level of your home this will be reflected in the value of your property. 

What is the going rate for a builder based on location?

LocationBuilder average hourly rate
North East£24
North West£26
South West£28

Builders will either work on a day rate, hourly rate, or a fixed fee. As property extensions take several weeks, the labour is a huge part of the cost. On average, builders in the UK charge between £24 and £28 per hour, which goes up to £43 per hour in London. 

Other considerations 

  • Fixtures and fittings - The fixtures and fittings will also determine the costs. Luxury materials such as Velux windows or marble flooring will add more costs to the project. Likewise, your extension will need insulation and external rendering. There’s also the cost of installing electricity and plumbing to consider too. 

  • Planning permission - Planning permission is of course the top consideration for any building work you wish to undertake. This especially the case if you live in a listed building. There will be costs associated with surveyors and architects, especially for more ambitious projects. If you have neighbours that live in close proximity you’ll also need to consider their needs too. If the building work is set to be disruptive, it’s always worth talking it through with your neighbours. You’ll also need to make sure any building work doesn’t encroach on their land or block the light from their property. 

Is it worth extending your property? 

If you love your home or the area you live in, but lack the space you need then absolutely. Extending your property can breathe new life into it, creating a warm and inviting space to raise your family in. 

As an example, many period properties have a small kitchen that’s not fit for dining or entertaining. A single-storey extension would greatly increase the amount of space you have for cooking in. 

Likewise, if you have a small ‘box room’ bedroom, a double-storey extension would turn this into a double room. Plus, it would add more living space downstairs too. If your extension is carried out to a high standard, it will most certainly add significant value to your home.

A property extension is one of the best ways to invest in your home. From new additions to the family to more usable space, they allow you to meet your space needs without having to move. 

Find local builders for your property extension with Bark. 

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