House Extensions: Which Types Make the Most Sense?

• Gavin Whitaker
• |
• April 20
• |
• house extensions

Thinking about a house extension but not sure where to start? It's a big move, and if you get it right, you'll gain space without needing to pack boxes for a full-on house move. Here's the deal: picking the right type of extension can give you everything from an open-plan kitchen to a new quiet bedroom or a work-from-home spot where you can actually concentrate.

Don’t get stuck comparing endless glossy photos. Start by asking yourself what you need: more bedrooms for a growing family, a smarter kitchen, or just a bigger space to stretch out? Your answer changes which extension is worth considering, so keep it real about your lifestyle and what bugs you most in your current setup. And hey, it’s not all about square footage—think about how you’ll use the space every day, and what’ll actually make your life easier.

• Most Popular Types of House Extensions
• What Extension Fits Your Home Style?
• Cost and Planning: What to Expect
• Hidden Traps and Smart Tips
• Boosting Value: Which Extensions Pay Off?

Most Popular Types of House Extensions

When people talk about house extensions, there are a few options that keep popping up because they actually work for most homes and budgets. No matter if you live in a bungalow or a two-story place, you’ll likely hear these types discussed again and again.

• Rear extensions: These are built right off the back of your house. They’re a winner if you want to open up your kitchen or add a dining area looking out onto the garden. Many families pick this type because it connects indoor space with the backyard, which is great for BBQs, kids, and pets. In the UK, most rear extensions fall under “permitted development,” meaning you usually won’t need full planning permission if you stay within set limits.
• Side return extensions: If you have that skinny alley running alongside your house, a side return lets you turn wasted space into a bright new kitchen, breakfast space, or hangout area. This is especially popular in Victorian and Edwardian homes where the original layout feels cramped.
• Wrap-around extensions: Here, you get the best of both worlds. It combines the rear and side return, wrapping the extension into an L shape. You’ll bag way more floor space, but it does cost more and takes a bit longer. Great if you want to totally change how downstairs feels.
• Single-storey vs. double-storey extensions: A single-storey extension is usually cheaper and quicker, mostly used for kitchens, playrooms, or ground-floor bathrooms. Go for a double-storey if you need extra bedrooms (or an upstairs bathroom), but know it’s going to be pricier and likely needs proper planning consent.
• Loft conversions: Not quite a "downstairs" extension, but worth a mention because they're so common. You add an extra room—like a bedroom or study—by building upwards. If you just need more room without eating into your backyard, it’s honestly a lifesaver.

Here's a quick look at how popular these options actually are in the UK, based on 2024 data from a trusted trade survey:

So, rear and single-storey extensions are topping the charts—not just because they’re practical, but because they’re often easier on your wallet and don’t send your neighbours calling the council. The right pick depends on your space, what you need, and how much you want to get involved with red tape. Once you have a feel for these types, it gets way easier to imagine what’ll actually work for you.

What Extension Fits Your Home Style?

Not every house extension looks good or works well on every type of property. The style, age, and overall layout of your house play a big role in what fits—and what just looks awkward.

If you’ve got a Victorian terrace, a big glass box on the back might stick out like a sore thumb. But a rear extension using brickwork to match the original home? That goes down way smoother. On the flip side, modern homes can handle bold lines and big windows without batting an eye.

Here’s a quick breakdown of what usually works best for the most common home styles:

• Semi-Detached and Terraced Houses: Side return or rear extensions are a hit here. They keep the flow and can open up cramped kitchens or living rooms, especially if you use similar brick or render to blend it in.
• Detached Houses: You’ve got more options—think wraparound, double-storey, or even a big orangery if you want a light-filled space. Pitch the roof to match the main house and don’t go overboard on glass if your house has smaller windows.
• Bungalows: Loft conversions and rear extensions can double living space without messing up the classic look. Use roof tiles and simple doors to keep things cohesive.
• Modern Builds: Go bold with glass walls, sharp corners, or even timber cladding. Just keep in mind what the neighbors look like; some streets aren’t fans of ultra-modern.

You might be tempted to copy a cool idea from Instagram, but check what your local planning rules are first. Some conservation areas are strict—think original style, matching colors, and no wild materials. For example, over 60% of UK councils say designs need to "complement the existing property." If you mess that up, you’ll get stuck in permission battles.

If you’re working with a builder or architect, ask them for photos of previous projects that fit your home’s era and style. And whatever you do, don’t mix old with new just because you saw it work somewhere else—what looked cool in a magazine might be a pain for resale value in your neighbourhood.

Cost and Planning: What to Expect

When you’re looking at house extensions, cost is the biggie nobody can dodge. Prices aren’t one-size-fits-all, but here’s a quick reality check: in the UK, single-storey extensions usually start around £1,800 per square metre. Want a two-storey job? Expect to pay roughly 50% more per extra floor because it means more engineering, more materials, and a lot more work. Fancier finishes, big windows, or a bespoke design can hike things up fast.

It’s not just the build cost. There are extra bits people forget: architect fees, planning applications, building control fees, and VAT. Architect fees can be 5%-15% of your extension budget. Planning application fees average around £250, but in some spots, you’ll pay more. Don’t ignore structural engineer costs if you’re knocking out walls.

Next up is planning. Not every house extension needs full planning permission—permitted development rules cover a lot of standard jobs if you stay within size limits and don’t live in a protected area. But if you’re pushing the size or live near neighbours (or in a flat), you’ll probably need formal permission. Always check your local council’s rules before calling a builder. It’s way easier to answer these questions upfront than sort out a legal mess after walls go up.

Typical steps for getting started the right way:

• Work out what you need—honest list, no fluff.
• Get an architect or a reliable building designer who knows local regs.
• Check if you need planning permission or can go for permitted development.
• Get several builder quotes—don’t just go with the first guy who smiles and promises a deal.
• Lock in full costs, including fees and a little buffer for random headaches (5-10% is smart).

Don’t forget the hidden costs of living in a building site—if your kitchen or bathroom is out of action, you might need to eat out or rent a portable loo. Budget for that too. Being realistic about timeframes helps. Most single extensions take 10–16 weeks, but delays from weather, supplies, or planning hiccups are super common.

Hidden Traps and Smart Tips

There’s nothing like finally getting that house extension only to stumble into headaches that could have been avoided. Here’s what catches people out, plus a few real-world tips that actually help.

The first trap? Not checking local planning rules. Every council has weird little quirks — some literally care if your new build overlooks a neighbor’s garden. Skipping this step can mean knocking down what you just built, or dealing with fines you absolutely do not want. Always check your local rules before moving a brick. In England, for example, single-storey rear extensions can often be built under ‘permitted development’ — but only if they fit size limits.

Then there’s the builder problem. Just because someone’s cousin built a nice porch doesn’t mean they’re ready for a full-blown home improvement gig. Always check references and work samples. The UK’s Federation of Master Builders or TrustMark are good places to look for people who know what they’re doing. If someone asks for a huge up-front payment, be cautious — it’s a common scam.

• Get a detailed written quote — not just a ballpark number.
• Demand clear payment milestones, like 10% after the foundation, not everything on day one.
• Ask for proof of insurance. If they damage your neighbor’s house, who’s paying?

Watch your budget. Surprises can and do happen. According to a 2024 survey by Houzz, more than 40% of extension projects ran over budget — mainly because homeowners forgot planning and design costs or hit snags with utilities like drains and gas lines.

Here’s another tip that’s easy to miss: upgrading your electrics and heating. New space often means your old systems need upgrades, which can tank your budget if you don’t plan for it early.

Last up, cheap windows and doors are a false economy. They might look fine at first, but you’ll feel every cold breeze and pay for it all winter. Good insulation matters just as much as how big your new room is.

So before you get too starry-eyed by fancy designs, double-check every detail, from planning to pipework. A brainy approach up front saves you cash, stress, and a lot of regrets down the line.

Boosting Value: Which Extensions Pay Off?

Add the right house extensions and you’re not just solving your own space problems—it’s like putting actual money into your home. But not all extensions are equal on the market. Some add way more value than others, and potential buyers notice the difference right away.

The golden ticket? A kitchen extension. Opening up your kitchen into a bigger, lighter space is easily the top value booster. According to Rightmove, homes with large open-plan kitchens or side-return kitchen extensions can fetch up to 20% more when it’s time to sell, especially in high-demand areas. People want space to cook, eat, and hang out—all in one spot. Add bi-fold doors opening onto the garden and you’re basically printing equity.

Second on the list: extra bedrooms. If your house extension adds a proper double bedroom and maybe a bathroom, you can jump your place up a whole price bracket. In lots of areas, a three-bed will attract way more buyers (and cash) than a two-bed, and adding a loft bedroom is sometimes less hassle than a double-storey build.

Check out how value can change depending on the extension:

Not every extension is a money-maker, though. Adding a luxury bathroom where there’s already enough doesn’t do as much for your home improvement bottom line—especially if you pinch space from bedrooms. And be careful with garage conversions; if parking is king on your street, turning the garage into a playroom could backfire.

Remember, costs should always be balanced with the likely boost in property value. Talk with local estate agents to get realistic numbers for your postcode, and double check that your planned extension will make sense for buyers in your area. The sweet spot? Creating flexible spaces people can use for all sorts of things—family life, working from home, or just relaxing. That’s what really pays off in today’s market.