Building a new home from the ground up, whether replacing an existing property or developing an infill plot, gives you complete control over layout, specification and performance in a way no renovation can match. In London in 2026, new build construction typically costs £2,200 to £3,500 per square metre at mid to high specification, excluding land, professional fees and VAT.

At a glance

  • Standard specification: £1,800 to £2,400 per square metre, typically outer London
  • Medium specification: £2,200 to £2,800 per square metre, inner or North London
  • High specification: £2,800 to £3,500+ per square metre, premium London locations
  • VAT: new dwelling construction is zero-rated for VAT, a significant saving over renovation or extension work
  • Planning: full planning permission is always required for a new dwelling

What a new build costs in London in 2026

For a typical four-bedroom house of around 160 square metres at medium specification, expect a construction cost of roughly £350,000 to £450,000, excluding land, professional fees and VAT. A five-bedroom house of 220 square metres at high specification in a premium location can run £570,000 to £770,000. These figures cover the core build only: foundations, structure, roof, windows, first and second fix services, and a standard internal finish.

One meaningful financial advantage of a genuine new build over an extension or renovation is that construction costs are zero-rated for VAT, provided the result qualifies as a new, self-contained dwelling. Professional fees remain subject to standard VAT, but the saving on the build cost itself is substantial.

Replacement dwellings and infill sites

A replacement dwelling means demolishing an existing house and building a new one in its place, generally viable where the existing building is beyond economic repair or where a better-designed, more efficient home is achievable on the same plot. Local planning authorities generally resist a significant increase in footprint or massing without strong design justification, so an early conversation with planners matters more here than on almost any other project type.

Small infill and windfall sites, underused or previously developed land within an established residential area, increasingly support new residential development under current local plans, though identifying a viable site and securing planning permission requires a targeted pre-application strategy rather than a speculative one.

Planning permission for a new dwelling

Unlike most extensions, a new build always requires full planning permission, since it creates a new dwelling rather than adding to an existing one. The application fee is calculated per 0.1 hectare of site area rather than per dwelling, and the process typically takes 8 to 13 weeks for a decision, though pre-application advice from the local authority is well worth the additional time it adds upfront.

Our new build process

We work with you and your architect, or provide design services ourselves, from initial feasibility and planning strategy through to a fully specified set of construction drawings. Once planning permission and Building Regulations approval are secured, our own groundworkers, bricklayers and tradespeople deliver the build from foundations to final decoration, with a dedicated site manager coordinating every stage.

Why choose Alpha London Builders for your new build

A new build is the largest financial and logistical commitment most clients will make, and we manage it with the same fixed-price, single-team approach as our other services, backed by structural engineering, Building Control liaison and party wall management where neighbouring properties are affected. See examples of our structural and extension work on our projects page.

Frequently asked questions

How long does it take to build a new house in London

Design and planning typically take 6 to 12 months, and construction itself generally runs 9 to 14 months depending on size and complexity, so allow 18 months to 2 years from initial feasibility to completion.

Is it cheaper to renovate an existing house than build new

Not always. A heavily extended renovation on a difficult existing structure can cost more per square metre than a straightforward new build, and a new build benefits from zero-rated VAT, which a renovation does not.

Can I self-build with your help rather than a full turnkey service

Yes, we work with self-builders in a construction-only capacity where the design and planning are already in place, as well as offering a full turnkey service from feasibility through to completion.

Do I need to demolish my existing house to build new

Only if you are pursuing a replacement dwelling. If you are developing an infill plot on land you already own, no existing structure needs to come down.

Speak to us about your new build or replacement dwelling project, and we will help you understand what is realistically achievable on your site.