New Build vs Renovation in London: Which Makes More Financial Sense?

**New build costs in London (2026, exc. land and professional fees):**

New build construction costs in London depend on specification, site conditions, and structure type:

• •**Basic specification** (brick/block, standard fixtures): £2,000–£2,800/m² (Gross Internal Area)
• •**Mid-specification** (quality finishes, good glazing specification): £2,500–£3,500/m²
• •**High specification** (bespoke architecture, premium materials, complex structure): £3,500–£5,500/m²

For a typical 160m² detached house: build cost £320,000–£560,000, excluding land, planning, professional fees, and landscaping/external works.

**Renovation costs in London (2026):**

Full renovation of a Victorian or Edwardian terrace involves retaining the existing structure and upgrading it to a modern standard:

• •**Cosmetic renovation** (redecoration, new kitchen, new bathrooms, minor repairs): £400–£900/m²
• •**Medium renovation** (structural openings, full M&E upgrade, plastering, kitchen/bathrooms): £900–£1,500/m²
• •**Full structural renovation** (major remodelling, new M&E, extensions, loft conversion): £1,500–£2,500/m² (of total floor area including new elements)

For a typical 120m² Victorian terrace with a 30m² extension: full renovation + extension, all-in: £150,000–£250,000, excluding land purchase costs and professional fees.

**The key cost comparison:** For equivalent floor area, renovation of an existing property is typically cheaper than a new build by 20–40%. The existing shell (walls, roof, windows, drainage) has already been paid for once — you are improving rather than constructing from scratch. However, old buildings can conceal expensive surprises (asbestos, structural issues, drainage problems) that new builds do not.

**Planning risk for new builds:**

Building a new house on a plot in London (demolishing an existing building or building on vacant land) typically requires full planning permission. This is a higher-risk planning route than householder extensions because:

• •New build proposals are assessed against the Local Development Plan, design codes, and character of the area
• •Height, massing, materials, and visual impact are all assessed
• •Conservation Area proposals are especially scrutinised — new buildings must be 'of equivalent quality' to the context and are often contentious
• •The council may require a Design and Access Statement, a Heritage Statement (if there is a listed structure nearby), and sometimes a planning viability assessment
• •Objections from neighbours are common and can delay decisions
• •Some boroughs are resistant to demolishing existing housing stock even to build new housing in its place

**Planning risk for renovation:**

• Renovating an existing building generally has a lower planning risk profile:
• •Extensions within PD limits do not require planning permission
• •Extensions requiring planning are householder applications — a simpler and more predictable process
• •The existing building's footprint and mass is established — you are not introducing a new massing into the street
• •Listed buildings present high planning risk for renovation (listed building consent required for most alterations), but non-listed Victorian and Edwardian stock is generally more straightforward

• **When new build planning can be easier:**
• •If the existing building is in poor structural condition and a certificate of lawful use confirms it is a redundant building
• •In some outer London locations where there is a clear need for housing supply and the site is allocated for development
• •Where the council has designated a site for residential development through a Site Allocation in the Local Plan

**New build timeline:**

• •Site acquisition: 2–6 months (conveyancing)
• •Pre-application planning advice: 4–8 weeks
• •Design and planning preparation: 4–12 months (complex schemes)
• •Planning application (full): 13 weeks statutory; often 6–12 months in practice
• •Technical design and Building Regulations: 4–8 weeks
• •Contractor procurement: 4–8 weeks
• •Construction: 12–24 months (depending on size)
• •Landscaping, commissioning, snagging: 2–4 months

**Total new build timeline (land found to completion): 3–5 years for most London new builds**

**Renovation timeline:**

• •Property acquisition: 2–4 months
• •Design (architect): 2–4 months
• •Planning (householder, if required): 2–4 months
• •Technical design and Building Regulations: 1–2 months
• •Contractor procurement: 1–2 months
• •Construction: 3–9 months (depending on scope)
• •Snagging: 2–4 weeks

**Total renovation timeline (property found to completion): 12–24 months for most significant renovation projects**

Renovation is typically 1–3 years faster than a comparable new build, primarily because planning risk is lower and construction is faster (you are not starting from foundations).

**For investment purposes (building to sell):**

The profitability of new build vs renovation depends primarily on the land/property acquisition cost relative to the end value (GDV — Gross Development Value).

A common development finance rule of thumb (the '70% rule') suggests that the total of land cost + build cost + professional fees + finance costs should not exceed 70% of GDV, leaving 30% for profit and contingency.

• In London, where land is very expensive:
• •A plot with planning permission for a 3-bed house in Zone 2–3 might cost £300,000–£600,000
• •Build cost for the house: £320,000–£480,000
• •Professional fees and finance: £60,000–£100,000
• •Total cost: £680,000–£1,180,000
• •GDV (selling price of the completed house): £700,000–£1,100,000 depending on location
• •Profit margin: often thin or negative in current London market conditions

• For renovation:
• •Buy a Victorian terrace requiring full renovation: £450,000–£700,000 (depending on borough)
• •Full renovation cost: £120,000–£200,000 (including extension)
• •Total: £570,000–£900,000
• •GDV: £700,000–£1,100,000 (depending on final specification and postcode)
• •Profit margin: typically 10–25% — better than many new build schemes in London

**For homeowners (building to live in):**

For a homeowner who plans to live in the property long-term, the new build vs renovation question is more about personal preference and aspiration than pure financial return:

• •A renovated Victorian terrace offers character, established neighbourhood, potentially lower initial purchase cost
• •A new build offers energy efficiency from the outset, modern layout, less maintenance in early years
• •For most London families, renovation of an existing Victorian property plus an extension is the most common and often most sensible path — it captures the character and location they want while creating the space they need