Should You Extend or Move House? A Practical Guide for London Homeowners

Should You Extend or Move House? A Practical Guide for London Homeowners

Meta title: Extend or Move House? A London Homeowner's Guide | RCB Design & Build

The Extend or Move Dilemma

Every year, thousands of London homeowners hit the same wall. The family is growing, the house feels tight, and the question becomes unavoidable: do we extend, or do we move?

It sounds like a simple financial decision, but it rarely is. It involves your finances, your family's lifestyle, your attachment to your home and neighbourhood, and your appetite for disruption. This guide helps you think through all of it clearly.

The Case for Extending

Extending makes sense when:

You love where you live. Your children are settled in schools, you know your neighbours, you're close to work, parks, friends, and your daily life is built around your current location. Uprooting all of that has a cost that doesn't show up in a spreadsheet.

The property has genuine potential. Not all homes extend well. But Victorian and Edwardian terraces, semi-detached houses with side returns or loft space, and houses with usable rear gardens can often deliver significant additional space without losing their character.

The move maths doesn't add up. Moving house is expensive. Stamp duty in London on a larger home can easily be £30,000 to £60,000 or more. Add estate agent fees (typically 1-2% of your sale price), legal fees, survey costs, removal costs, and the cost of getting the new home to the standard you want, and the total can be eye-watering before you've even started decorating.

You can stay during works. For many extensions and loft conversions, it's possible to remain in the property during construction. It requires tolerance, planning, and a good contractor — but it avoids the disruption and cost of temporary accommodation.

The Case for Moving

Moving makes sense when:

The property genuinely can't deliver what you need. Some homes cannot realistically be extended to the size you need, whether because of planning constraints, the layout of the existing building, or the garden space available.

You've outgrown the neighbourhood. Schools, commute, proximity to family — these things change. If the area no longer suits your life, an extension won't fix that.

The extension would over-capitalise the property. In some streets, spending extensively on works can take the property above the ceiling value for that road. A good estate agent or chartered surveyor can tell you what the comparable sales look like and whether the investment would be recoverable.

You need to move anyway for other reasons. Proximity to a new job, a change in family circumstances, or downsizing — if the move is happening regardless, extending first rarely makes sense.

The Real Cost of Moving in London

People often underestimate how expensive it is to move. Consider:

• Stamp Duty Land Tax — on a £900,000 purchase with no first-time buyer relief, SDLT alone is approximately £38,750. On £1.2m it rises to £73,750.
• Estate agent fees — typically 1-1.5% of sale price plus VAT.
• Conveyancing and legal fees — for both sale and purchase.
• Survey costs — a full structural survey on an older property can be £1,000-£2,000.
• Removal and storage costs.
• Renovation and decoration at the new property.

When you add these up, a house move in London can easily cost £80,000 to £120,000 in transaction costs alone, before you touch the new house.

The Real Cost of Extending

Extension costs depend on the scope and specification. But the key point is that with a well-designed, properly managed extension or loft conversion, you're creating space that:

• Has no transaction cost attached to it
• Adds value to the existing property
• Allows you to stay in a neighbourhood you know

The money stays in your asset rather than going to the government, agents, and solicitors.

Questions to Ask Before You Decide

What would the space actually look like? Commission a concept study from an architect before committing. It costs relatively little and tells you whether the extension you're imagining is buildable, whether planning is likely to be an issue, and what you'd actually get.

What does the market say? Ask a local estate agent what your extended home would be worth versus what a comparable larger home would cost to buy. The gap is one of the most useful numbers you can get.

What is your disruption tolerance? Some families find living through a build manageable; others find it miserable. Be honest with yourself.

What is your timeline? Extensions and loft conversions typically take 12-20 weeks from start on site. The pre-construction phase — planning, design, structural engineering, tender — can add another 3-6 months. Moving can happen faster, though a competitive market can delay it too.

Making the Decision

There is no universal right answer. But the homeowners who most regret not extending are those who moved primarily because they assumed extending was too expensive or too disruptive — only to discover that the move cost more, took longer, and left them in a house they liked less.

If you're genuinely torn, the most useful thing you can do is get both options properly costed before deciding. Talk to an estate agent and a design-and-build contractor. The numbers, not assumptions, should drive the decision.

At RCB Design & Build, we help London homeowners understand what's genuinely achievable with their property before committing to anything. If you'd like to explore what extending could look like for your home, we're happy to start that conversation.