Most people come to this question assuming renovation is the sensible, affordable option and new build is for people with deep pockets and a lot of patience. The reality is more nuanced than that, and in London specifically, the maths does not always work the way people expect.

Both routes have genuine advantages. Both have risks that get underplayed. And the right answer depends on your site, your budget, your timeline, and what you actually want to end up with.

This guide does not have an agenda. We build new homes for a living, so you might expect us to favour new build. But the honest answer is that renovation is the right call for some projects and new build is the right call for others. What follows is a straight comparison of the two routes across cost, planning, timeline, energy performance, and the factors that tend to tip the decision one way or the other. If you want to understand what a new build actually costs in London, our guide to new build costs in London has the detail.

The Cost Comparison: What the Numbers Actually Look Like

Cost is where most people start, and it is the most misleading part of the comparison if you only look at headline figures. Here is what the current London market looks like in 2026.

New build construction costs

For a new build in London in 2026, construction costs run from roughly £2,500 per square metre at standard specification to £4,000 per square metre or more for high spec or complex designs. A four-bedroom house of around 160m² carries a construction cost of somewhere between £400,000 and £640,000.

That does not include land, professional fees, planning, or the structural warranty. Add those in and the total project cost on a typical London new build for a four-bedroom home sits somewhere between £600,000 and £900,000 all-in, depending on location and specification.

Renovation costs

Renovation costs in London in 2026 typically run from £800 to £1,200 per square metre for a light refurbishment through to £2,500 to £3,500 per square metre for a full gut-and-rebuild including structural alterations. A mid-range full renovation on a 110m² three-bedroom house, covering new kitchen, bathrooms, rewire, replumb, insulation, and replastering, sits broadly between £150,000 and £250,000.

At face value, renovation looks significantly cheaper. But there are costs built into renovation that new build does not carry, and they change the comparison more than most people account for.

The costs renovation hides

This is where the comparison gets complicated.

• VAT. New build construction is zero-rated for VAT. Renovation is standard-rated at 20%. On a £300,000 renovation contract, that is £60,000 in VAT that you would not pay on an equivalent new build. This is one of the most significant and least understood financial advantages of building new.
• Hidden structural problems. Old London housing stock carries surprises. Inadequate foundations, outdated drainage, asbestos, failed party walls, damp penetration, timber rot, and outdated wiring are all common. A pre-purchase survey gives you some picture but it cannot see everything. Budget overruns of 20 to 40% are not unusual on significant renovations of older London properties once the walls come off.
• Energy retrofitting costs. Meeting modern energy standards in an old building is genuinely difficult and expensive. Insulating a solid-wall Victorian terrace to a decent standard involves either internal insulation that reduces floor area or external insulation that changes the appearance. Neither is cheap and neither produces results as good as a purpose-built new home with modern fabric from the start.
• Ongoing maintenance. An older building will always cost more to maintain than a new one. That cost is diffuse and hard to budget for, but over a 10 to 20-year horizon it is real money.

Cost Factor	New Build	Renovation
Construction cost per m² in London	£2,500 to £4,000	£800 to £3,500 depending on depth of works
VAT on construction labour and materials	Zero-rated (0%)	Standard-rated (20%)
Professional fees	5 to 15% of build cost	5 to 15% of project cost
Hidden or unforeseen costs	Lower risk: you control the spec from scratch	Higher risk: older buildings hide problems
Energy retrofitting	Not required: built to current standards	Often significant cost to meet modern standards
Stamp Duty Land Tax	Only on land purchase, not construction cost	On full property purchase price if buying to renovate
Ongoing maintenance	Lower for the first 10 to 20 years	Higher, especially on pre-1919 stock
Structural warranty	Required, £1,500 to £3,500	Not required on existing stock

The VAT saving on a new build is often large enough to close the gap between construction costs when the two are compared fairly. On a £500,000 construction contract, zero-rating saves £100,000 compared to a renovation of equivalent value. That is not a rounding error.

Planning: Which Route Is Harder?

This is the question most people get wrong. The common assumption is that renovation is simpler from a planning perspective because you are working with an existing building. In London, that is not always true.

Planning for renovation

Many renovations do not need planning permission. Internal alterations, like-for-like replacements, and work within permitted development rights can proceed without a formal application. But in London, permitted development is more restricted than elsewhere. Conservation areas, Article 4 Directions, listed building status, and the sheer density of the housing stock mean that more renovation work needs planning consent in London than in most other parts of the country.

A significant renovation that changes the external appearance, extends the building, or alters a listed property requires full planning permission. Getting that permission can be just as challenging as a new build application, and the constraints on what you can do are often tighter because you are working within an existing context that planners want to protect.

Planning for new build

New builds always require full planning permission, which is a guaranteed cost and programme commitment. In London, planning takes a minimum of eight weeks for a standard application, and in practice longer. But a new build on a cleared site gives you more design freedom than a renovation. You are not constrained by the existing layout, the existing structure, or the planning history of a building that has been altered repeatedly. Our guide to common reasons planning permission gets rejected in London covers what to watch out for.

Conservation areas: the London-specific complication

Over 300 conservation areas exist in London. If your property is in one, both renovation and new build face heightened scrutiny. For renovation, this means matching existing materials and detailing, which adds cost. For new build, it means a design that sits comfortably within the historic character of the area, which limits some design choices but does not make new build impossible.

Neither route has a blanket planning advantage in a conservation area. The quality of the design and the pre-application work you do with the council matters far more than whether the project is a renovation or a new build.

Timeline: How Long Does Each Route Take?

Stage	New Build	Renovation
Design and planning	6 to 18 months	3 to 12 months
Pre-construction surveys and approvals	3 to 6 months	1 to 3 months
Construction	12 to 24 months depending on size	3 to 18 months depending on scope
Total from first conversation to moving in	2 to 4 years typically	6 months to 2 years typically
Disruption during construction	You can usually stay elsewhere while building	Often requires decanting, especially on full renovations

New build takes longer, and that is simply the reality of commissioning a new dwelling from scratch. If your timeline is the primary constraint, renovation is usually faster. But faster does not mean smoother. Renovation programmes are less predictable than new build programmes because of the unknown condition of the existing building. A new build on a cleared site is easier to programme and sequence because you are not working around an existing structure that reveals problems as you go.

Energy Performance: Where New Build Has a Clear Advantage

This is the area where new build wins most decisively, and it matters more in 2026 than it has ever done.

A new build designed to meet the Future Homes Standard will be dramatically more energy efficient than any pre-1980 London home and significantly better than homes built as recently as 2013. It will have no gas connection, a heat pump as standard, solar panels on the roof, triple or high-performance double glazing, exceptional insulation throughout, and mechanical ventilation that maintains air quality while recovering heat from extract air. The energy bills will be substantially lower than comparable older properties.

Retrofitting an older home to an equivalent energy standard is possible but expensive and rarely achieves the same result. Solid walls are harder to insulate than purpose-built new build walls. Draught-proofing an old building to modern airtightness standards requires intrusive work throughout. Replacing a gas heating system in an older property with a heat pump often requires upgrading radiators, rerouting pipework, and sometimes restructuring the building’s fabric to accommodate lower flow temperatures.

The running cost difference between a new build home and a renovated Victorian terrace compounds over years. On energy bills alone, the gap can amount to several thousand pounds per year. That does not make renovation wrong, but it is a real cost that belongs in the long-term comparison.

What New Build Gives You That Renovation Cannot

• Complete design freedom. Layout, room sizes, orientation, window positions, ceiling heights: all of it starts with a blank sheet. You are not working around what someone built 100 years ago.
• A building that performs to current standards from day one, with no compromises on insulation, airtightness, or heating.
• A 10-year structural warranty as standard, which renovation does not carry.
• No stamp duty on the construction cost. You pay stamp duty only on the land purchase, not on what it costs to build.
• Zero VAT on construction labour and materials.
• Predictable costs. Once the specification is fixed and the contract is signed, the scope of a new build is known. An old building always carries the risk of finding something unexpected once you open it up.

What Renovation Gives You That New Build Cannot

• Speed. A renovation is almost always faster than a new build from start to move-in.
• Character. Period properties in London have features that are genuinely difficult to replicate: ceiling heights, original cornicing, fireplaces, solid brick walls, original timber floors. If those things matter to you, renovation preserves them in a way new build cannot.
• An established location. Renovation often means staying in a house and street you already know and like, rather than taking on the uncertainty of a new build site in a different part of the borough.
• Lower upfront capital. Even accounting for VAT and hidden costs, a renovation on an existing property you already own is typically a lower total capital commitment than buying land and building from scratch.
• Planning certainty in some cases. For straightforward renovation within permitted development, you can start work without a planning application. That is never the case for a new build.

So Which One Actually Makes More Sense?

The honest answer is that it depends on the specific situation. But here are the conditions that tend to push the decision one way or the other.

New build makes more sense when:

• You own or can acquire a cleared or clearable plot in a location you want to be in.
• The existing property on a site is beyond economic renovation, structurally compromised, or simply not worth saving.
• You want a home designed precisely for how you live, rather than adapted from an existing layout.
• Energy performance and long-term running costs are a serious priority.
• You have time: two to four years from first conversation to moving in is realistic and you can absorb that.
• You want to avoid the uncertainty of discovering structural problems once renovation work begins.

Renovation makes more sense when:

• You already own the property and the existing structure is sound and worth working with.
• The character of the existing building matters to you and is genuinely hard to replicate.
• Your timeline is tight and you cannot commit to a two to four-year new build programme.
• The scope of work is relatively contained, such as a kitchen, bathrooms, rewire and redecoration, rather than a ground-up rebuild.
• Planning constraints make new build on the site difficult or the principle of development is uncertain.

The scenario where neither answer is obvious is a significantly run-down property in a good location where the cost of full renovation approaches the cost of demolition and new build. In London, this happens more often than people expect. A Victorian terrace in poor condition with structural problems, outdated services, and no insulation can cost as much to bring to a modern standard as a new build would cost on the same footprint, and still not achieve the same result. In those cases, the new build calculation starts to look compelling even accounting for the planning process.

Not Sure Which Route Is Right for Your Project?

We work across all 33 London boroughs and have priced and delivered both new builds and major renovation projects. If you want an honest view of which route makes more sense for your specific site and budget, talk to our team. No sales pitch, just a straight conversation about what the numbers look like.

DEVELOPER NOTES

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Frequently Asked Questions

Is it cheaper to renovate or build new in London?

On a raw per-square-metre basis, renovation often appears cheaper than new build. But the comparison is less straightforward than that headline suggests. Renovation attracts 20% VAT on labour and materials, which new build does not. Renovation of older London properties regularly encounters hidden structural problems that push costs well above the original estimate. And bringing an old building to modern energy standards adds significant cost that a new build does not carry. On a fair like-for-like comparison that accounts for all of these factors, the cost difference between a serious renovation and a new build on the same site is often smaller than people expect.

Do I pay VAT on a renovation?

Yes. Renovation and repair work on existing residential properties is standard-rated at 20% VAT. New build construction is zero-rated at 0%. On a large renovation contract this is a significant difference. There is a reduced rate of 5% that applies to some conversion work and to renovations of properties that have been empty for two or more years, but standard renovations are charged at 20%. Our guide to VAT on new builds covers the full picture.

Can I knock down my house and build a new one in London?

Yes, in most cases. Demolishing an existing house and building a new one in its place is a well-established route in London, and one of its advantages is that the principle of residential development on the site is already established. You will need full planning permission for the new dwelling, and you may need a separate demolition consent depending on the location. In conservation areas, demolition consent is required in addition to planning permission for the new build. The new build on the cleared site qualifies for zero-rated VAT on construction.

Is renovation faster than new build?

Generally yes, though the gap varies significantly depending on the scope of the renovation and the complexity of the new build. A contained renovation can be completed in a few months. A full gut-and-rebuild renovation including structural work can take 12 to 18 months. A new build from first conversation to moving in typically runs two to four years once you include design, planning, surveys, and construction. If your timeline is the primary constraint, renovation is usually the faster route.

Which is better for energy efficiency, new build or renovation?

New build is significantly better. A new build designed to meet the Future Homes Standard, which came into force in 2027, produces at least 75% less carbon than homes built to 2013 standards and has no gas connection, a heat pump, solar panels, and high-performance fabric from day one. Achieving an equivalent energy standard through renovation of an older London property is possible but expensive, technically difficult, and rarely produces the same result. The running cost difference between a well-built new home and a renovated Victorian terrace can amount to several thousand pounds per year.

What about the character of older London homes?

This is the one area where renovation has a genuine advantage that new build cannot replicate. Victorian and Edwardian London properties have ceiling heights, room proportions, original features, and a sense of solidity and permanence that modern construction finds hard to match. If those qualities matter significantly to you, they are a real argument for renovation. The question is whether they are worth the additional cost, the planning constraints, the energy performance gap, and the maintenance burden that comes with an older building. For some people the answer is clearly yes. For others, once they work through the numbers, it is less obvious.