A house extension in London is an excellent way to add space and value to your home, but it’s crucial to understand the costs involved before starting. With so many factors at play—size, materials, labour, and location—it’s easy to feel overwhelmed.
This guide will break down the key elements that influence house extension costs in London, provide average price ranges for different types of extensions, and offer budgeting tips to help you plan your project with confidence.
1. How Much Does a House Extension in London Cost?
London house extensions typically cost more than projects elsewhere in the UK due to the demand for skilled labour, high-quality finishes, and the complexity of urban planning regulations. Here’s an updated breakdown of costs by extension type:
Single-Storey Extension: £2,500–£3,500 per square metre
Double-Storey Extension: £3,000–£4,000 per square metre
Side Return Extension: £80,000–£120,000
Wraparound Extension: £120,000–£200,000
Basement Extension: £5,000–£7,000 per square metre
These costs cover structural work, materials, labour, and planning but can increase with additional features like bespoke joinery or luxury finishes.
2. Breaking Down the Costs
Here’s what typically makes up the total cost of a house extension in London:
a. Design and Planning
Architectural Drawings: £2,000–£8,000, depending on the complexity.
Planning Permissions: £200–£500 for application fees. Listed buildings or conservation areas may incur higher costs for consultations and adjustments.
b. Materials
High-quality materials like natural stone, timber, and steel cost more but elevate the finished product. Costs vary widely depending on your preferences:
Standard Materials: From £80 per square metre.
Luxury Materials: Can range from £150–£300 per square metre.
c. Labour Costs
London’s competitive market means labour costs are higher than in other regions. For skilled builders and tradespeople, expect:
Builders: £150–£250 per day per worker.
Specialist Trades (e.g., Electricians, Plumbers): £250–£350 per day.
d. Interior Finishes
The quality of interior finishes can significantly impact costs:
Standard Finish: £100–£150 per square metre.
Luxury Finish: £200–£400 per square metre.
3. Factors That Affect House Extension Costs
Several factors can influence the total cost of your extension:
a. Property Type
Victorian and Georgian homes often require careful structural updates to blend modern designs with period features.
Conservation areas and listed buildings may require additional permissions and specialist expertise.
b. Size and Scale
Larger extensions naturally cost more but may offer better value per square metre, especially for double-storey projects.
c. Custom Features
Bespoke features like skylights or hidden storage solutions can add to the overall cost while enhancing functionality and style.
4. Additional Costs to Plan For
Beyond the visible construction work, consider these additional expenses:
Party Wall Agreements: £700–£1,500 per neighbour, depending on the complexity.
Structural Engineer: £1,500–£5,000 for detailed calculations.
Contingency Budget: Set aside 10–15% for unexpected costs like foundation work or delays.
5. Cost Comparisons by Extension Type
Single-Storey Extensions
Ideal for expanding kitchens or living rooms, these are the most straightforward projects.
Cost Range: £50,000–£100,000.
Best For: Creating open-plan layouts or extending into a garden.
Double-Storey Extensions
Offers twice the space for less than double the cost of a single-storey.
Cost Range: £100,000–£200,000.
Best For: Adding bedrooms, bathrooms, or a home office.
Side Return Extensions
Maximises unused space alongside your home, ideal for London terraces.
Cost Range: £80,000–£120,000.
Best For: Narrow properties or creating bright, open-plan kitchens.
6. How to Budget for Your House Extension
a. Establish Priorities
Define your must-haves (e.g., number of rooms, specific finishes) and allocate your budget accordingly.
b. Plan for Hidden Costs
Commonly overlooked expenses include:
Relocating utilities like gas meters or boilers.
Groundworks for uneven or sloping plots.
c. Optimise Value
Focus on high-impact areas like kitchens or living spaces that increase property value and enhance daily life.
7. Why Invest in a House Extension in London?
Increase Property Value: Extensions can add 10–20% to your home’s value, making them a smart investment.
Improved Lifestyle: Create spaces tailored to your family’s needs, from open-plan living to a home office.
Cost-Effective Alternative to Moving: Avoid stamp duty and moving costs while staying in your neighbourhood.
8. Why Choose Canyon for Your London House Extension?
At Canyon Design and Build, we specialise in high-quality, bespoke extensions designed to meet your needs and exceed your expectations. Our expert team handles every stage, from initial design and planning to construction and finishing touches, ensuring your project is seamless and stress-free. With years of experience navigating London’s unique challenges, we’re the trusted choice for homeowners across the city.
A house extension in London is a significant investment, but with careful planning and the right team, it can transform your home and lifestyle. By understanding the factors that influence costs and setting a realistic budget, you can approach your project with confidence.
Ready to get started? Contact Canyon Design and Build today to discuss your dream extension.
Comments