Every single storey extension I’ve been involved with starts the same way — someone standing in their kitchen, pointing at a wall, saying “I just want it to feel bigger.” That’s the easy part to picture. What’s harder to picture, if you’ve never done this before, is everything that happens between that conversation and the day builders actually turn up with a skip.
So here’s what a proper job should actually look like, and what you should genuinely expect if you’re hiring a London design and build company rather than trying to piece the whole thing together yourself, trade by trade.
It Should Start With a Site Visit, Not a Sales Pitch
The first red flag with any company is if they’re happy to give you a price without seeing your house. Single storey extensions all look similar on paper — a box added to the back of a property — but every garden, every boundary, every set of existing drains is different, and that affects both design and cost more than people expect.
A proper first meeting involves someone walking the site, asking how you actually use your home day to day, and being honest early on about what’s realistic given your plot and your local council’s history with similar applications. I’ve seen homeowners get attached to a design pulled straight from a magazine, only to find out later their garden’s narrower than they thought, or there’s a protected tree at the back that limits how far they can build. Better to find that out in week one, before a single drawing’s been paid for, than three months into the process.
Design That’s Actually Grounded in the Structure
This is where the phrase “design and build” earns its keep rather than just sounding good on a website. With a genuine London design and build company, whoever’s drawing your extension is already thinking about how it gets built — where the steel needs to go, how the new roof ties into the existing one, whether the kitchen layout you’re picturing actually works with where the drains currently sit.
Compare that to hiring an architect on their own, disconnected from anyone who’ll actually build the thing. They can produce something genuinely beautiful, but if they’re not talking to a builder throughout, you sometimes end up with drawings that look perfect on paper and need reworking the moment someone prices them properly. That back-and-forth eats time, and it almost always eats money too.
Planning Permission Handled Properly, Not Just Mentioned in Passing
Plenty of single storey extensions fall under permitted development and don’t need full planning permission, but that’s never guaranteed — it depends on your property, what’s already been extended before on that plot, and your specific council’s approach. A decent design and build company should tell you clearly and early whether you’re likely to need permission, and what a realistic timeline looks like if you do.
What you shouldn’t be doing is submitting drawings yourself and hoping for the best, or discovering halfway through construction that building regulations sign-off was never actually arranged. Both should sit within the service you’re paying for, not treated as somebody else’s job or an afterthought once the build’s already underway.
A Clear, Fixed Price Before Anything Starts
This is probably the biggest gap between a good experience and a genuinely stressful one. You should be handed an itemised quote that reflects what’s actually being built — not a vague figure that quietly grows every few weeks because of “unforeseen issues.” Real unforeseen issues do happen, especially with older London properties, but they should be the exception you’re told about openly, not a pattern baked into how a company operates.
At London Design & Build, pricing is agreed upfront and held to. If something genuinely unexpected turns up once walls are open, we talk it through with you before doing anything about it — never after the invoice has already landed on your doorstep.
One Point of Contact, Not Three
With single storey extensions specifically, the trades involved are fairly predictable — groundworkers, bricklayers, roofers, electricians, plumbers, plasterers — but coordinating them badly is exactly how straightforward projects turn into overrunning ones. If you’re managing that yourself, or your architect, engineer and builder aren’t actually speaking to each other, you become the go-between by default, chasing everyone for updates nobody seems to have.
A proper project manager removes that entirely. You should have one person to call with questions, someone who genuinely knows what stage the build’s at and what’s happening next week, rather than someone reading off a schedule they’ve never actually visited in person.
Communication That Doesn’t Go Quiet in the Middle
The middle of a build is where communication tends to fall apart with less organised outfits — the exciting bit’s over, the finish line still feels far off, and updates start thinning out. With a properly run London design and build company, that shouldn’t happen. You should expect regular, honest contact throughout the whole process, not just enthusiastic updates at the start and a rushed handover at the end.
What Handover Should Actually Feel Like
A finished project isn’t just “the builders have left and taken the skip.” There should be a proper snagging process, someone checking the small details before anyone calls it done, and a team that’s still reachable weeks later if something needs attention — a door that’s sticking slightly, a tap that needs adjusting. That aftercare is part of what proper design and build services should include, not a favour you have to ask for.
Getting Started
If you’re weighing up a single storey extension, the right first step isn’t picking tiles or browsing kitchen brochures — it’s a proper, honest conversation with someone who’ll tell you what’s genuinely achievable on your specific property, your budget, and your council’s track record, rather than whatever sounds best in a sales pitch.
In Conclusion: Why Homeowners Choose London Design & Build
This is exactly the standard we hold ourselves to at London Design & Build. We’re a London-based design and build company that keeps architects, structural engineers, and the construction team working together from the very first site visit through to the final snag being closed off — not a loose collection of subcontractors operating under one banner. Every client gets a dedicated project manager, a fixed price we commit to and hold, and a team that handles planning permission and building regulations as standard, not as an extra.
Whether you’re leaning toward a single storey extension or still deciding what’s right for your home, we offer a free site visit that takes less than a minute to arrange. Get in touch with London Design & Build today, and we’ll give you an honest, tailored answer on what to expect for your specific property.
