Extending your home is a great way to create more living space and potentially increase your property’s value. Understanding the costs involved is essential before committing to such a project. The cost of a house extension can vary widely based on several factors, including; location, size, type of extension and materials used. Here we’ll explore how much you can expect to pay for different types of extensions, what factors affect the overall cost and how to make your extension as cost-effective as possible. 

Why undertake a home extension? 

Home extensions are popular for various reasons. If you’re running out of space or need additional rooms,extending your home can be more practical than moving to a new property. Extensions can accommodate growing families, create open-plan living areas or add dedicated work-from-home spaces. They also have the potential to boost your home’s market value. However, not all extensions guarantee a high return on investment, so it’s important to weigh the costs against the benefits. You also need to consider your financing options and whether you’d need to take out a home improvement loan or other finance to begin your dream extension. 

How much will a house extension cost you? 

The cost of a house extension in the UK can range from £1,000 to £2,500 per square metre, depending on various factors. This wide range reflects the differences in location (with London and the South East generally being more expensive), the materials used and the complexity of the design. Larger extensions, high-end finishes and more complex structures will naturally be on the higher end of this price range. In addition to the construction costs, don’t forget to factor in planning permission, architectural drawings and potential costs for any structural adjustments to the existing house. 

Types of home extensions 

There are various types of extensions, each with different costs, benefits and uses. The most common include single-storey, two-storey, garage conversions, loft conversions and rear extensions. Each type offers different possibilities for improving your living space and property value, but each comes with its own unique price point and set of considerations. 

Factors affecting the average house extension cost 

Several factors can influence your house extension cost. These include the size and complexity of the extension, the materials used, your location and any necessary groundwork or demolition. Planning permissions, building regulations and party wall agreements (particularly in semi-detached or terraced houses) can also add to the cost. Labour charges are another major factor, with costs varying significantly depending on whether you are in a high-cost area like London or a less expensive region. 

How much do house extension drawings cost? 

Before any work begins, you’ll need professional architectural drawings for your extension, which typically cost between £500 and £1,500 depending on the complexity of the project. These drawings are essential for securing planning permission and ensuring that the extension is built to meet building regulations. More intricate or larger designs will require more detailed drawings, which can raise the cost. While this is an additional upfront expense, it’s essential and ensures your extension is well-planned and legally compliant. 

Extension cost by type 

Each type of extension offers different possibilities for adding space and value to your home. The costs of each vary and will depend on the type of extension you choose. 

Single-storey extension 

Single-storey extensions cost between £1,500 and £2,000 per square metre. Ideal for extending kitchens or living spaces, they’re more affordable than multi-storey extensions. Relocating utilities may increase costs. 

Two-storey extension 

Two-storey extensions cost £1,800 to £2,500 per square metre. They add space on two levels, making them more cost-effective per square metre, though additional structural work can raise the final price. 

Semi-detached house extension 

For semi-detached homes, expect to pay £1,500 to £2,000 per square metre. A party wall agreement with neighbours may be required, adding time and cost to the project. 

House side extension 

Side extensions cost £1,000 to £2,000 per square metre. These are a smart way to use redundant side space, often for kitchen expansions or utility rooms, without major structural changes. 

Garage conversion 

Garage conversions range from £5,000 to £15,000. They add extra living space, such as a home office or gym, without heavy structural work. 

Loft conversion 

Loft conversions cost between £20,000 and £50,000. A simple room conversion is cheaper while adding dormers and windows increases the price. They’re great for adding bedrooms or offices. 

Rear house extension 

Rear extensions cost £1,500 to £2,500 per square metre. They’re perfect for creating open-plan living spaces but may cost more if groundwork or utility relocation is needed. 

How to save money on an extension 

Saving money on a home extension is possible with some smart planning. Start by choosing standard, budget-friendly materials instead of expensive bespoke options. A simpler design, like a basic rectangular layout, will keep construction straightforward and reduce costs. Consider where you can handle some work yourself, such as painting or small finishing tasks, as this will lower labour expenses. 

Another key tip is to plan thoroughly from the start. Rushed decisions or last-minute changes can lead to delays and increased costs, so it’s important to finalise your design before work begins. Compare multiple quotes from builders and always keep a contingency fund available for any unexpected costs. Preparation and careful choices can make a real difference in getting the most from your budget. 

Balancing the cost and value of your home extension 

Extensions can add valuable space to your home and improve its appeal, but not all types guarantee a high return on investment. By understanding the costs, choosing the right type of extension for your property and being mindful of your budget, you can ensure that your home extension adds both comfort and value to your living space. With the right finances in place, you can plan your dream extension, you should just make sure to get as much as you can from your money. 

If you want to learn more about homeowner loans for your home extension, arrange a chat with one of our broker partners.