How Much do House Extensions Cost in the UK?

How Much do House Extensions Cost in the UK?

A house extension can be a fantastic way to increase the square footage of your home and increase the property’s value, but how much do house extensions cost and what should you expect to pay to upgrade your home in this way?

In this article, we’ll look at the factors that impact the house extension cost and give you a clear idea of how much homeowners typically pay for an average extension.

House Extensions plans and visual showing design before and after

Understanding House Extension Costs

Before you begin to gather quotes and get estimates for an extension, it’s important to consider how house extension costs work. Does an estimate include the cost of materials, for example? Similarly, understanding the range of work and the expertise required to add an extension to a property will allow you get a more in-depth understanding of the costs involved.

Factors Affecting House Extension Costs

There are numerous factors that can affect house extension cost. Firstly, the type of house extension you opt for, and the amount of work required will affect the overall pricing. A loft conversion may be cheaper than a double-storey extension, for example.

There are many different types of extension that can enhance a property, such as:

  • Wrap-around extension
  • Rear extension
  • Side return extension
  • Double-storey extensions
  • Loft conversions
  • Conservatories

While the type of extension you choose will significantly impact the cost of the project, this isn’t the only element that will affect the overall price. Other factors can have a considerable impact on house extension cost too, such as:

  • Size of extension
  • Materials used (e.g., double or triple-glazed windows)
  • Planning permission and building regulations
  • Groundworks
  • Interior features (e.g., kitchen or bathroom)
  • Skills, experience and expertise of the team
  • Décor

As you might imagine, the cost of a house extension tends to increase the larger it is, so a sprawling double-storey extension is likely to be more expensive than a compact rear extension. Similarly, an extension that’s intended to be used as a kitchen or bathroom will be more costly to fit out than an extension that will be used as a study or playroom, for example.

Many people ask, how much do house extensions cost, but, as you can see, there are numerous variable factors that must be taken into account when determining the price of an extension.

If you’re looking for a ballpark figure, however, the cost of a standard room extension is typically around £3,000 per square metre for the build, although this can increase to approx. £4,000 per sq. m depending on the spec of the project.

Kitchen home extension with dark blue and grey cabinets and tiles

Average Costs for Single-Storey Extensions

A single-storey extension provides you with extra space on the ground floor of your property, which can be used in a variety of ways. A kitchen extension, bathroom extension, side return extension and wraparound extension can all take the form of a single-storey extension and will increase the functionality of your home.

While the cost of a single-storey extension will depend on the specific parameters of the project, an average cost of £3,000 per square metre for the build can be applied. So, if you’re planning a 20m2 single-storey extension, for example, you can expect to budget around £60,000 for the build.

Average Costs for Double-Storey Extensions

Double-storey extensions can add a substantial amount of extra space to a property as you’re extending both the ground and first floor of your home. Again, the size and type of extension you choose will have a significant impact on cost.

However, using the benchmark of £3,000 per square metre, you can expect a 60m2 double-storey extension to cost around £180,000. In some cases, it may be possible to reduce the cost of a two-storey extension as some elements of the project, such as the groundworks, only need to be carried out once.

Conservatory Extension Costs

A conservatory can be a fast and cost-efficient way to add extra space to your home, as planning permission isn’t usually required. Many people are choosing this type of extension to create new rooms, such as work-from-home offices or home gyms, for example.

When it comes to costs, conservatory extensions vary wildly in pricing. A uPVC lean-to conservatory can be noticeably cheaper than a conservatory formed from regular building materials, for example.

As a type of side extension, we can apply the standard figure of £3,000 per square meter for the build to conservatories too. For a conservatory that delivers 16 square metres of space, for example, the cost can be around £39,000 for the build.

Cream kitchen extension

Kitchen Extension Costs

If your kitchen is the heart of your home, this may be where you want to extend the most. Creating a large kitchen gives you the opportunity to incorporate a dining area into the space or to transform the area into an open-plan living space, for example.

For kitchen extensions, the average estimate of £3,000 per square metre still applies to the build but it should be noted that the cost of installing a new kitchen can increase the overall cost of the project. It may be more realistic, therefore, to use the higher end of the average pricing and assume a cost of £4,000 per square metre for kitchen extensions, alongside the cost of a new kitchen.

Loft Extension Costs

Loft conversions don’t always require planning permissions, which means they are a popular way for homeowners to create more space. There are many different types of loft extensions to choose from, including:

The type of extension, as well as its size and the current condition of the roof structure, will impact the house extension cost. A Velux loft conversion is usually the cheapest option, with projects starting from around £22,500 – £30,000 for a 30 square foot loft, for example, while the average cost of a hip-to-gable loft extension is around £55,000.


Builder using measurements to cost a home extension in the UK

Planning Permission and Building Regulations Costs

If planning permission is required, you will need to pay the relevant application fee to your Local Planning Authority. Currently, the fees in England are as follows:

  • Full planning permission – £206 for alterations/extensions to a single dwelling
  • Outline planning permissions £426 per 0.1 hectare of land (up to 2.5 hectares)

However, do factor in the cost of having the plans for your extension drawn up by a professional architect. As well as enhancing the appearance and functionality of the extension, professionally prepared plans can increase the chance of your planning application being approved upon its first submission.

If you need to submit a Buildings Regulations application, you’ll also be required to pay the relevant fee to your local council. The cost of this does vary depending on the type, size and complexity of the project and may vary from one council to another.

If this sounds daunting it needn’t be, as Copperwheat Conversions we can take care of all plans, structural calculations and building control as part of our service.

Reducing House Extension Costs

All homeowners want to reduce the cost of house extension wherever possible and there are ways to minimise your expenditure when you’re expanding your home. For example:

  • Careful planning from the start of the project can lead to big cost savings throughout the build.
  • Choosing a fully insured building company will ensure that the financial consequences of unexpected accidents are covered.
  • Reduce the size of your proposed extension to minimise costs.
  • Compromise on materials to keep expenditure low.
  • Choose to decorate the interior of your extension yourself to avoid extra expense.

Choosing the Right Contractor for Your House Extension

Finding the right contractor is essential if you want your house extension to be successful. As well as providing you with a fair price, the right contractor will ensure that the work is carried out safely, efficiently and in accordance with your requirements.

At Copperwheat Conversions, we pride ourselves on delivering an exceptional standard of work, regardless of what type of extension you’re planning. With free quotes and fully inclusive estimates available, why not contact our team to learn more about house extension costs now?