House Extensions

London Builders – Professional House Extensions

There’s something genuinely exciting about extending your home. In a city like London, where every square metre of land is worth its weight in gold, a well-executed extension is the smartest alternative to relocating. Instead of dealing with the stress of stamp duty and moving fees, you can make your current property work harder for you. Whether it’s a rear kitchen diner or a multi-storey side extension, you’re not just adding “extra room”—you’re completely changing the flow of your daily life.

At Force Builders Ltd, we’ve spent over two decades seeing how a structural addition can breathe new life into a tired floorplan. It’s about creating better space, not just more of it. Maybe you need a sun-filled open-plan kitchen for the family, a dedicated home office that’s actually quiet, or an extra bedroom for a growing family. We handle the heavy lifting, from digging the footings to the final coat of paint, so you can stay in the neighbourhood you love while enjoying a home that feels brand new.

Understanding Different Types of Extensions

Every London property—from a Victorian terrace in Camden to a 1930s semi in Ealing—has its own structural quirks. Choosing the right type of extension depends on your plot size, the existing foundations, and your budget. We specialise in several key formats:

• Single-Storey Extensions: Perfect for expanding your ground floor. These are often used for “wraparound” projects or simple rear additions to create large, open-plan living zones with bi-fold doors and roof lanterns.
• Double-Storey Extensions: If you need serious square footage, going up two levels is the way to do it. You get extra living space downstairs and a new master suite or bathroom upstairs. Surprisingly, the cost per square metre is often lower than a single-storey build because the expensive groundworks and roofing costs are shared across two floors.
• Side-Return Extensions: A classic London solution for Victorian homes. We reclaim that narrow, unused “alleyway” at the side of your house. It might only be a few feet wide, but it completely transforms a cramped galley kitchen into a wide, bright space.
• Orangeries & Conservatories: For those who want to bridge the gap between the house and the garden. Modern orangeries with brick pillars and high-performance glazing provide a solid, year-round room that doesn’t get too hot in summer or freezing in winter.

Planning Permissions and Building Regulations

Navigating the red tape in London can be a nightmare if you don’t know the local council’s quirks. We help our clients manage the entire process, ensuring every brick laid is 100% legal.

Many projects fall under Permitted Development (PD) rights, meaning you don’t need full planning permission as long as you stay within certain limits regarding height and depth. However, if you live in a Conservation Area or a listed building, the rules change. We often recommend applying for a Lawful Development Certificate just to have that peace of mind in writing.

Regardless of planning, Building Regulations are mandatory. This covers the “unseen” but vital parts of the build:

• Structural Integrity: Calculating the correct size for RSJs (steel beams) to support the floors above.
• Insulation & Thermal Performance: Using high-spec PIR boards or mineral wool to meet U-value targets.
• Fire Safety: Ensuring correct escape routes and fire-rated doors where required.
• Drainage & Plumbing: Proper connection to the main sewer lines and vent stacks.

Design, Materials, and Light

An extension shouldn’t look like a “stuck-on” box; it should feel like it’s always been there. We pay close attention to the brick match and the roofline to ensure a seamless transition. For some modern projects, we use contrasting materials like zinc cladding or charred timber (Shou Sugi Ban) for a striking architectural statement.

Maximising natural light is our priority. In deep London terraces, the middle of the house can become dark once you extend. We solve this by strategically placing Velux windows, frameless roof lights, or large-format sliding glass doors. It’s not just about aesthetics—natural light makes a room feel twice as large as it actually is.

The Reality of Costs and ROI

Let’s talk numbers. In the current market, a London extension typically costs between £1,800 and £3,000 per square metre, depending on the spec. A standard 30m² kitchen extension might sit in the £55,000 to £85,000 bracket. We always advise a 15% contingency fund for those “surprises” that often hide under the floorboards of old houses.

The good news? The Return on Investment (ROI) in London is excellent. Adding a double bedroom and an en-suite can increase your property’s value by 20% or more. In many postcodes, the value added by the extra space far outweighs the construction costs, making it a sound financial move as well as a lifestyle one.

Why Choose Force Builders Ltd?

Choosing the right contractor is the difference between a smooth build and a total headache. We don’t believe in “guesstimates.” We provide a detailed schedule of works and a clear contract. You’ll know when the steels are arriving, when the skip is being swapped, and when the electrician is due for the second fix.

We work closely with architects and structural engineers to ensure the design is practical. Our team handles everything: excavation, damp proofing, joist work, and final finishes. We’ve built our reputation on being transparent, reliable, and obsessed with the details that other builders skip.

Ready to start your extension project? Get in touch with Force Builders Ltd today. We’ll arrange a site visit, look at your drains and boundaries, and give you an honest assessment of what you can achieve with your budget. Let’s build the space you’ve been dreaming of.

FAQ: House Extensions

Do I need planning permission for a small extension? Not always. Many of our projects in London fall under Permitted Development. If you aren’t going crazy with the height or pushing too deep into your garden, you can usually skip the council paperwork. That said, some London boroughs have their own quirks. It’s best if we just come over, take a look at the site, and tell you straight if you need to file an application or not.

Is it going to cost me a fortune? Look, every house in the UK is different, so anyone giving you a flat price over the phone isn’t being straight with you. A side-return on a Victorian terrace is a completely different beast than a simple rear extension. We prefer to walk through the space with you, see what we’re dealing with structurally, and then give you a realistic number. No fluff, just what it actually costs to get the job done right.

Can I stay in the house while the work is happening? You can, and most people do. We won’t sugarcoat it—it’s going to be dusty and there will be noise. But we’re used to working around families. We keep the site as tidy as possible and make sure you’ve got a working kitchen and bathroom for as long as we can. If you can handle a bit of chaos for a few weeks, you’ll save a lot on rent.

How long until I can actually use the new space? If everything goes smoothly, you’re looking at about 2 to 3 months of actual building time. The weather is obviously the big “if” here in the UK. We don’t like to rush the foundations or the structural bits just to hit a date, but we’ll keep you posted every week on where we’re at.

Is an extension actually worth the investment? In London? Almost always. With the way house prices and stamp duty are, it’s usually much cheaper to build out than to move. You’re adding square footage and, more importantly, making the house actually work for your lifestyle. It’s one of the few home improvements where you’ll likely see every penny back when you eventually sell.