How much does a home extension cost in 2024?

There’s no one size fits all when it comes to a expanding your home. The price per m/sq will depend on the size of your extension, construction type, e.g. timber frame construction or masonry construction, materials used and quality of finish. In 2024, our luxury, single-storey extensions cost roughly £3,000 per sq/m.

In the UK, Check A Trade says that for a standard small (15m²) rear house extension, the cost is around £30,000 – £42,000. For a medium (30m²) rear house extension, the cost is around £40,000 – £56,000. For a large (50m²) rear house extension, the cost is around £100,000 – £140,000. These prices will vary depending on the region/city/town, but are a good indicator as to how much your extension could cost you.

Building regulations for home extensions

Building regulations approval is necessary for all extensions and is typically obtained by submitting a building control application to the local authority.

  • Building regulation prices are determined by the size and complexity of your home extension.

  • A structural engineer typically costs £1200-£3000

  • An approved inspector will cost about £850-£1550

  • CCTV drainage survey £250-£500

  • Party wall surveyor will cost about £350-£600 (plus any additional costs per hour)

Overall, the costs involved are around £2000-£4000 for a smaller project, and £3000-£5000 for a larger one.

Using these figures, we can calculate the cost of your planned extension. At a cost of £3,000 per metre, we’ll multiply it by the total m² of the space you want to create. For example, a modern, rear extension with a 5-star finish that measures 7x3 metres will cost from £63,000 +VAT.

If you wanted to add a modern kitchen to your extension that has a high-quality finish and inlcudes luxury appliances, prices start from £20,000 +VAT. In addition to plumbing, you’ll need gas and electrics, plus extra costs will be incurred if you plan to purchase a new boiler or move a boiler.

What affects the cost of a home extension?

There’s lots to consider when building a single-storey extension, including:

Size of Extension: The biggest cost of a house extension is the build cost (materials and labour). The larger the extension, the larger the cost.

Insurance: This will likely increase your premium but it’ll be necessary to let your home insurance company know of upcoming works to ensure you’re covered during the development work and that your new extension is included in the policy once complete.

Planning Permission: Not all extensions need planning permission as they fall under permitted development rights. For more information on what’s required view the official Government site.

Architects: Our team of architects will work with you to come up with the perfect design that suits your requirements, secure accurate quotes and aid with the planning permission process.

Clearing the space & Groundworks: There’s often a lot that needs doing before any work can begin, such as removing trees and shrubbery, dismantling awnings and patios and moving drains. Depending on the extent of work here, the cost can increase.

Windows & Doors: During the design process, we’ll discuss what windows and doors you’d like and if you’d want a roof lantern.

Finishing & Fittings: Once you have your home extension is built, you’ll need to decorate it. From kitchen accessories to bespoke finishing, the costing will be as unique as your home extension.