London and The West Midlands’Leading Home Extension Specialist
London and The West Midlands’Leading Home Extension Specialist
A home, kitchen, or side return extension is a fantastic way to add extra space and increase the value of your property — especially in London, where space is at a premium. But one of the most common questions we hear is: how much does an extension cost?
Extensions are increasingly popular with homeowners across the UK. While they offer valuable additional space, they may also affect your finances if you decide to re-mortgage. That’s why it’s essential to understand the full cost implications before moving forward.
At BuildUp Loft & Extension, we’ve been designing and building quality home and kitchen extensions for over 12 years. Our experience gives us deep insight into extension costs, including the price of materials, labour, and potential hidden expenses.
Understanding the cost of a house extension can be challenging. Many variables influence the final price — such as property size, type of extension, finishes, and your location within the UK. Labour rates, in particular, can vary significantly between regions.
While an extension can add long-term value to your property, it’s important to consider both the upfront cost and ongoing running costs. You should also set aside a contingency budget to cover any unexpected changes or requirements that arise during the build.
Whether you’re considering a rear, side, or wraparound extension, our team can provide a tailored quote and guidance based on your unique needs and budget.
During the recent pandemic, the cost of building a home extension has risen due to shortages in both labour and materials. That’s why it’s more important than ever to do your research before appointing an architect or builder.
Depending on the size, the type of space required, and your location, the average cost of a house extension typically falls between £50,000 and £85,000, though costs can go higher depending on your specific requirements.
At BuildUp Loft & Extension, every project we undertake is tailored to the unique needs of our clients. Naturally, this means the cost of each extension can vary significantly. However, to help you plan, we’ve compiled some average price estimates as a general guide — please note these figures are ballpark and for reference only.
We’re also happy to provide a more precise estimate tailored to your project. Our team offers free, no-obligation site surveys, where one of our experienced representatives will visit your property, discuss your goals, and prepare a fully itemised quote outlining all costs involved.
Side return extension costs typically start from £50,000 and up, depending on the size, internal specifications, and your location. Regional differences in labour and material costs can affect the overall price, so it’s important to get a personalised quote based on your property.
A side return extension makes use of the narrow alleyway to the side of your home — often a small space that delivers a big transformation. Though compact, this type of extension can significantly improve the layout, light, and usability of your kitchen or dining area.
If your home allows for it, a side return extension is one of the most cost-effective ways to enhance your living space without major structural changes. It’s especially popular in Victorian and Edwardian terraced homes, where side alleys are common.
A small house extension in London typically costs between £50K – £60K, but determining an accurate price can be challenging due to several influencing factors. One key factor is the location of the extension—whether it’s at the front, rear, or side of your home. For instance, the cost of a rear kitchen extension may differ from that of a side extension designed as a bedroom.
At BuildUp Loft & Extension, we understand how vital it is to get precise pricing before you begin. Our team offers free site surveys, where we visit your property, assess the space, and discuss your design preferences and specifications in detail.
💬 Book your free quote today and let BuildUp help you bring your vision to life.
A rear extension—as the name suggests—is a box-style structure typically added to the back of a property, often expanding the kitchen or living space. Rear extensions come in various shapes and sizes and can have a transformational impact on your home.
Unlike side return extensions, rear extensions may reduce your garden space and, depending on their size, could require planning permission.
In London, the average cost of a rear extension is around £60K. However, pricing varies based on several factors, including the extension’s size and internal finishes such as flooring, glazing, heating, and decoration.
At BuildUp Loft & Extension, we recommend booking a free site survey with one of our experts to receive a fully itemised quote tailored to your property and requirements.
💬 Get your free quote today.
Single storey extensions are similar to a rear extension but can be carried out on any side of the home including the front and side. They are popular on homes which have a lot of exterior space on all sides to extend into. An average single storey extension cost will start at approximately £50K upwards, depending on the size of the project. Extension costs will always vary so it is important you seek an accurate price before you sign any contract between yourself and your builder.
A wrap around extension combines both a rear and side return extension, wrapping around the existing structure of the home. Because of the expanded footprint, this type of extension tends to cost more than single-direction extensions—but the impact is significant.
Wrap around extensions make the most of all available side and rear space, creating a large open-plan area that often includes a stunning kitchen, dining room, and even a relaxation or family zone.
In London, wrap around extensions typically start from £75K and upwards, depending on the overall size, design complexity, and internal specifications such as glazing, fixtures, and finishes.
At BuildUp Loft & Extension, we offer free site surveys to assess your space, understand your vision, and provide a clear, detailed quote.
💬 Get your free quote today.
The cost of double storey extensions are naturally at the higher end of a home renovation cost, due to the size and complexity of constructing them as well as needing scaffolding for work at a higher level. Double storey extensions are less popular in London due to the large amount of external space that is usually required. However, if you have the space and budget available for one, they can be a fantastic addition to any family home as they can add extra bedrooms and living space both upstairs and downstairs.
Double storey extensions cost from £85K upwards in London. Again, the prices of double storey extensions can vary dramatically, depending on the internal finish required as well as any specifications needed for windows, doors, decorating etc. Some clients also like to combine a double storey extension with alterations to the ground floor such as making a kitchen bigger or adding a ground floor toilet. Whilst additional work around the home can add extra cost to your extension project, sometimes there can be savings to be made by appointing one contractor to handle all elements.
Detailed double storey extension costs can be found by booking a free site survey with the Buildup Extend team. This way you will get a truly accurate price for an extension with our team. Get a free quote today.
When extending your home, many clients choose to renovate other rooms at the same time—such as bathrooms, living rooms, or bedrooms. This approach offers both cost savings and reduced disruption, as the same contractor handles all the work in one go. It also ensures a consistent finish and standard of quality throughout your home.
At BuildUp Loft & Extension, we also offer the option to combine a loft conversion with a ground floor extension, helping you maximise your home’s potential. Whether you’re looking to create extra bedrooms, a home office, or an open-plan family space, our experienced team can manage both projects seamlessly.
While combining a loft conversion and extension naturally increases the overall cost, it often results in better value, as shared planning, materials, and labour can help you save in the long run.
💬 Talk to us today about a full-home transformation.
The cost of building an extension can sometimes work out more cost-effective than moving home as not only can it be cheaper, but it can also add value potentially in the long term. Aside from the extension costs, there can be many other costs to remember when it comes to building your dream project:
At BuildUp Loft & Extension, we’ve successfully delivered a wide range of extensions across London and the West Midlands, working with homeowners on projects of all sizes and budgets. If you’re looking to manage costs more effectively, here are a few smart ways to keep your extension within budget:
Be mindful of internal specifications: High-end kitchens, bespoke fittings, and premium materials can quickly increase costs. For kitchen extensions in particular, shopping around for the best kitchen deals can lead to significant savings.
Choose smart glazing options: Instead of a fully glazed roof, consider installing Velux roof windows. They’re more cost-effective and still allow a great amount of natural light into your space.
Opt for budget-friendly flooring: Materials like laminate or luxury vinyl tiles can give a stylish finish at a fraction of the price of real wood or ceramic tiles.
Our experienced team is here to guide you through the process. Book a free home survey with one of our specialists to discuss cost-saving tips, design solutions, and get a tailored quote that works for your budget.
To get a better idea of how an extension can transform your space—or to explore the quality of our workmanship—visit our Types of Extensions and Gallery sections for real examples of completed projects.
Every build by BuildUp Loft & Extension includes a range of high-spec features such as premium windows, flooring, plumbing, and electrics. We also offer a variety of bespoke options to suit your individual taste and requirements.
Need a loft conversion too? Through our sister company BuildUp Loft, we can provide detailed loft conversion costs. All of our surveyors are trained to quote for both home extensions and loft conversions, so if you’re considering both, we can cover everything in a single site visit.
📞 Contact us today to discuss your extension requirements and receive a detailed, no-obligation cost breakdown.
Book your free site survey by calling +44 7771 377253, emailing thomasbuilderteam@gmail.com, or filling out our easy online enquiry form.
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Extensions Kitchen Extensions – House Extensions – Flat Roof Extensions – Side Return Extensions – Wrap Around Extensions – Rear Extensions
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