How long does a London house renovation really take?

Almost every enquiry we receive contains the same question, usually somewhere near the end: how long will this actually take? It is the fairest question a client can ask, and the hardest one to answer in a sentence — because the building work is rarely the longest part of the programme.

What follows is how a London renovation genuinely unfolds, phase by phase, and the local conditions that quietly add weeks if nobody is watching for them.

The short answer

For a well-run London project, expect roughly three to six months of preparation before anyone lifts a tool, then three to twelve months on site depending on scope. A cosmetic flat refurbishment can be designed and delivered inside six months end to end. A whole-house renovation with a rear extension and a loft conversion is realistically a twelve to twenty-month commitment from first meeting to handover.

The single biggest programme risk is not the build. It is starting on site before the design, the consents and the costs are genuinely settled.

The phases, and what each one takes

Brief and feasibility — 2 to 4 weeks

You decide what the project is for. A measured look at what the property can take, an early view on whether consents are likely, and an honest first budget band. Time spent here is repaid several times over.

Survey and existing drawings — 1 to 3 weeks

A measured survey produces accurate existing plans and elevations. Where you are extending or digging, you may also need a topographical survey, drainage investigation or asbestos refurbishment survey. Booking these early avoids a two-week hole later.

Design — 4 to 10 weeks

Concept, then developed design, then the technical package your builder will actually price and build from. Clients often compress this stage and pay for it during the build in variations and delays.

Planning and consents — 8 weeks to several months

A householder planning application in England carries a statutory determination target of eight weeks, though validation, consultation and committee schedules routinely push it further. Listed building consent, conservation area scrutiny and any objections extend it. If the work falls under permitted development you may still want a Lawful Development Certificate for certainty — read our guide to planning permission versus permitted development, and see how we handle applications under planning permissions and approvals.

Tender and cost plan — 3 to 6 weeks

Issuing a complete package to two or three contractors, reviewing returns properly, levelling the exclusions and agreeing a contract. Rushing this is how budgets drift.

Mobilisation — 2 to 4 weeks

Contract signed, insurances checked, building control appointed, party wall matters concluded, skips and parking arranged, protection and welfare set up.

Strip-out and structure — 3 to 10 weeks

Soft strip, temporary works, underpinning or steel installation, openings formed, new foundations and slabs. This is the noisiest, dustiest and most disruptive stretch, and the one most exposed to surprises behind old plaster.

First fix — 3 to 6 weeks

Studs, floor structures, drainage, pipework, cabling, ventilation, window installation and the building envelope closed up. Plastering follows once the shell is watertight and dry.

Second fix — 3 to 6 weeks

Doors, skirtings, sanitaryware, electrical accessories, joinery installation and the kitchen. This phase is entirely dependent on materials being on site.

Finishes — 2 to 5 weeks

Decoration, flooring, stone, tiling, lighting commissioning, ironmongery. Detail work that cannot be hurried without showing.

Snagging and handover — 2 to 4 weeks

A proper snag list, remedial works, testing and certification, then the operation and maintenance information, warranties and building control completion certificate. We continue afterwards through post-renovation support and maintenance.

What moves timelines in London

• Listed buildings. Listed building consent runs alongside planning and reaches into detail most people do not expect: windows, floor build-ups, services routes, even paint finishes. Allow months, not weeks.
• Party walls. Under the Party Wall etc. Act 1996, notices for cutting into or altering a party structure require two months' notice, while line-of-junction and excavation notices require one month. Adjoining owners have fourteen days to respond, and silence counts as dissent, which means surveyors and an award. Serve early.
• Leaseholder consent. In a flat, your lease almost certainly requires the freeholder's written licence to alter. Obtaining it involves solicitors, a fee and often a surveyor's review. Three months is common and it cannot be compressed by wanting it more.
• Parking, skips and access. Suspending bays, licensing a skip or scaffold and applying for permits all take lead time from the borough, and some streets simply have no room. On tight terraces this dictates the sequence of the whole build.
• Working hours and neighbours. Most boroughs restrict noisy works to weekday daytime hours with reduced Saturday working. Basements and structural phases feel slower as a result.
• Utilities. New or upgraded supplies, meter moves and service diversions are booked through the network operators and run to their calendar, not yours.
• Lead times on the good things. Bespoke joinery, stone, specialist glazing and made-to-order sanitaryware are frequently the critical path. Selecting these during design, not during second fix, is the difference between a smooth finish and an empty room waiting for a worktop.

Protecting your programme: a short checklist

1. Fix the brief before the design develops, and resist reopening it after tender.
2. Commission surveys early — measured, drainage, asbestos where relevant.
3. Take a planning view in week one, even if the answer is "permitted development, with a certificate".
4. Serve party wall notices as soon as the structural design is settled.
5. Start the freeholder licence to alter the day you know you need one.
6. Tender a complete package, not a sketch, and read the exclusions.
7. Approve long-lead items — joinery, stone, glazing, kitchen — before work starts on site.
8. Agree a written programme with the contractor and review progress against it weekly.
9. Hold a realistic contingency of time as well as money.
10. Make decisions in batches, on a schedule, so the site is never waiting on you.

Where we come in

A programme survives on sequencing: knowing what has to be decided in March so a wall can close in July. That is the work of project management and coordination — one point of contact, one schedule, and every consultant and trade held to it. You can see the results across our projects, or tell us about your property and we will give you an honest first view of the timescale.

This article is general guidance for London homeowners, not professional advice. Programme durations vary with scope, property and borough, and statutory procedures change — always confirm current requirements with your local authority and appointed consultants.