How much does an extension, or remodel cost….?

In the United Kingdom, residential extensions have become an increasingly popular choice for homeowners looking to expand their living space without the hassle of moving. Whether you're considering a single-story rear extension, a loft conversion, or a two-story side extension, it's crucial to understand the costs involved in such projects. In this blog post, we'll explore the factors that influence residential extension costs in the UK and provide you with a rough estimate to help you plan your extension project effectively.

Extension Types and Costs

The type of extension you choose significantly impacts the overall cost. Here are some common extension types and their approximate costs:

• Single-Story Rear Extension: Typically, this involves expanding the ground floor of your home to create a larger living area or kitchen. Costs for a single storey extension can range from £2,000 to £3,500 per square meter, depending on location, design and materials.

• Loft Conversion: Converting your loft into a habitable space is an excellent way to gain extra room without altering your home's footprint. Costs can vary from £1,000 to £2,500 per square meter, depending on the complexity of the conversion. The average cost for a basic loft conversion incorporating Velux rooflights is £15,000-£20,000. For a conversion with a dormer, the price range is £30,000-£60,000.

• Two-Story Side Extension: This extension type involves adding two stories to the side of your home, significantly increasing your living space. Costs for a double storey extension can range from £2,000 to £3,500 per square meter, depending on location and design.

• Major internal works to include a total re-model of the existing layout (structural works, knock through walls). The costs for major internal works can range from £1,500 to £2,500 a square meter. More decorative refurbishment (not knocking through walls, more minor works) you would need to factor in around £1,000 - £2,000 a square meter.

Before starting your extension project, you'll need to check whether the scheme requires planning permission, in some instances you can undertake the works under the permitted development guidelines, it is important to check with the Architect, Architectural Designer or local authority prior to commencing the work. The design process will incur additional costs for application fees and architect fees. The complexity of your design, such as the need for structural alterations, bespoke materials, or special features, will also influence the overall cost of the fee paid. You can expect to pay from £3,000 - £15,000 (or more should the Architect be managing the build process) in Design/Architects Fees, Application fees, Building Control fees, Structural engineers fees, party wall or other consultants fees depending on the complexity of the project. So when budgeting for your project please make sure you have a contingency for professional fees.

Location Matters

The location of your property can significantly affect extension costs. In general, areas with higher property prices tend to have higher building and labor costs. For example, London and the South East typically have higher extension costs compared to other regions in the UK. You would be expecting to pay the higher rates in these locations.

Project Size and Scale

The size and scale of your extension project have a direct impact on the final cost. Larger extensions, as well as multi-story extensions, will naturally cost more than smaller, single-story ones. Keep in mind that adding bathrooms or kitchens will increase costs due to installation, plumbing and electrical work.

Building Materials

The choice of building materials can significantly affect your extension costs. High-end materials like hardwood or custom-built features will increase the overall expenditure. Conversely, using standard materials and finishes can help keep costs down. Windows and doors contribute to a huge percentage of the build cost, high end slim line sliding doors, steel doors and bespoke rooflights will be considerably more expensive than alternatives such as UPVC, generic aluminium profiles, Velux rooflights. It is important to speak in detail about your aspirations on the finishes to your designer, they will be able to advise you on choices which fit within your budget and manage expectations.

Labour Costs

Labour costs, including builders, electricians, plumbers, and other tradespeople, can constitute a substantial portion of your extension budget. Labour costs can vary depending on location, the complexity of the project, and the level of experience of the contractors. Some trades people may not be registered for VAT and this can add to a saving if not using one large main contractor, however it is always advisable if you are not experienced in running construction projects to employ a main contractor who will oversee and coordinate the various trades and health & safety on the project.

Contingency Budget

It is advisable to set aside a contingency budget of 10-20% of the total project cost to cover unexpected expenses or changes in plans. This will help you avoid financial stress should any unforeseen issues arise during the construction phase.

Understanding the costs associated with residential extensions in the UK is essential for effective project planning. The final cost of your extension will depend on various factors, including the type of extension, location, design complexity, materials, and labour costs. By considering these factors and conducting thorough research, you can create a realistic budget and ensure that your extension project proceeds smoothly. Remember that while extensions can be a significant financial investment, they often add value to your property and provide you with a more comfortable and spacious living environment.