How long does a full house renovation take?

A full gut renovation of a London house (strip to brick, full rewire, full replumb, structural alterations) typically takes 12–18 months from initial design to completion. A moderate renovation (new kitchen, bathrooms, some structural) takes 6–9 months. A light cosmetic refresh can be done in 2–4 months.

What takes longest in a renovation project?

The pre-construction phase — design, planning, building regulations and contractor procurement — is almost always the longest single element for major projects. A planning application alone typically takes 10–16 weeks in London boroughs. Combined with design and contractor selection, projects often spend more time in pre-construction than on site.

Can renovation phases overlap to save time?

Yes — an experienced project manager or architect can run building regulations applications, contractor tender and procurement concurrently, saving 4–8 weeks on major projects. However, appointing a contractor before building regs are approved carries risk if regs require design changes. Good procurement is about sequencing risks intelligently, not compressing the programme at the expense of certainty.

Should I move out during a house renovation?

For a full gut renovation or structural project, moving out is strongly recommended. The noise, dust, loss of kitchen and bathroom facilities, and the safety implications of an active building site make living in the property extremely difficult. For moderate renovations, it depends on the scope and programme — some homeowners remain in partial occupation throughout, but expect significant disruption. Extensions and loft conversions are usually liveable — the work stays above or outside the existing occupied spaces.

Renovation Project Timeline

Q: How long does a house extension take in London?

A single-storey rear extension in London typically takes 9–12 months from start to handover — including the pre-construction phase (design, planning or PD approval, building regs, contractor selection) and the build itself. The build-only programme is usually 16–26 weeks. Extensions requiring full planning permission add 3–6 months to the overall timeline.

Q: How long does a loft conversion take in London?

A permitted development loft conversion in London typically takes 7–11 months from commission to handover. The on-site works take 12–20 weeks, but the pre-construction phase (design, building regs, party wall, contractor selection) adds another 10–20 weeks before any work starts on site.

How long will my project actually take? Answer two questions to get a realistic, phase-by-phase timeline — from first design meeting to handover keys.

One of the most common surprises in renovation is how long the pre-construction phase takes. Planning, building regulations, contractor selection and procurement can easily add 3–6 months before a single brick is laid. This tool maps the full journey so you can plan realistically.

Generate your project timeline

Two quick questions, then we'll map your project phase by phase — including the parts that happen before anyone sets foot on site.

Step 1 of 2

What type of project are you planning?

Step 2 of 2

Indicative project timeline

total weeks

approximate months

Click any phase row to expand details about what happens during that stage.

Pre-construction

On-site works

Finishing & handover

All timescales are typical ranges for London projects based on our direct experience. Individual projects can be faster or slower depending on contractor availability, planning authority response times, site conditions and design complexity. Always build in contingency.

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Why does pre-construction take so long?

Most homeowners focus on the build programme — the weeks when contractors are on site. But for any project involving planning permission, building regulations or party wall notices, the pre-construction phase is often longer than the build itself.

A typical rear extension, for example, will spend 16–24 weeks in design, approvals and procurement before the first shovel goes in — and then 16–20 weeks on site. Understanding this from the outset helps you plan your temporary accommodation, manage your expectations, and avoid the frustration of feeling like nothing is happening.

The good news: with experienced professionals running the project, many pre-construction phases can overlap. Building regulations can be submitted while you're tendering to contractors. Procurement can start before regs are approved. A well-run project loses far fewer weeks to sequential bottlenecks than one that waits for each sign-off before starting the next step.

Typical project timelines at a glance

Project type	Pre-construction	On-site works	Total (design to handover)
Single room cosmetic refresh	3–6 wks	3–6 wks	6–12 wks
Single room full refit	4–11 wks	5–11 wks	10–22 wks
Full flat renovation	8–14 wks	11–20 wks	19–35 wks
House renovation (moderate)	9–15 wks	10–20 wks	21–35 wks
House renovation (full gut)	14–28 wks	17–36 wks	31–65 wks
Rear extension (PD)	16–24 wks	14–27 wks	30–51 wks
Rear extension (planning)	19–33 wks	14–26 wks	33–60 wks
Loft conversion (PD)	10–19 wks	14–23 wks	27–47 wks
Loft conversion (planning)	19–33 wks	14–23 wks	36–58 wks
Extension + loft (PD)	17–27 wks	22–43 wks	40–70 wks
Extension + loft (planning)	23–39 wks	22–43 wks	46–80 wks

When should I book my builder?

In London, good main contractors with a strong track record are typically booked 8–16 weeks in advance. For larger projects — extensions, loft conversions, full house renovations — it is not unusual for the best contractors to be booked 4–6 months ahead.

The right time to start conversations with contractors is as soon as your architect has produced tender drawings — even if planning permission or building regulations are not yet approved. Most experienced contractors will provide a quote and provisionally hold a start date while approvals are in progress. Waiting until everything is signed off before approaching contractors is the single most common cause of avoidable programme delays.

Planning delays: the biggest programme risk

London boroughs are legally required to determine householder planning applications within 8 weeks. In practice, many take 12–16 weeks — and contested or complex applications can take considerably longer. Pre-application advice from the Local Planning Authority (LPA) is strongly recommended before submitting, and can significantly reduce the risk of refusal or lengthy back-and-forth with the planning officer.

If an application is refused, the timeline resets: revisions, resubmission and a new 8-week determination period add months to the programme. An experienced architect with strong local knowledge of your borough can dramatically reduce this risk.

Related guides

Frequently Asked Questions

How long does a house extension take in London?

A single-storey rear extension under Permitted Development typically takes 7–12 months from commission to completion — around 16–24 weeks in pre-construction (design, PD prior approval, building regs, contractor selection) and 16–26 weeks on site. If full planning permission is needed, add 3–6 months to the pre-construction phase. Build a realistic programme with your architect from day one and allow a 10–15% contingency on both time and cost.

How long does a loft conversion take in London?

A permitted development dormer loft conversion in London typically takes 27–47 weeks in total from commission to completion. The on-site works take 14–23 weeks, but the pre-construction phase (design, structural drawings, building regs, party wall notices, contractor appointment) adds another 10–20 weeks. Mansard conversions requiring planning permission add a further 10–16 weeks for the planning process.

Do planning applications actually take 8 weeks in London?

Rarely. London boroughs have a statutory 8-week target for householder applications, but many consistently take 12–16 weeks. Busy boroughs in inner London can take even longer during peak periods. Pre-application advice is strongly recommended before any submission — it reduces the risk of refusal or officer requests for additional information that reset the clock. Some boroughs offer a paid fast-track pre-application service that can significantly improve certainty.

Can I live in the house during a renovation?

It depends on the scope. For a full gut renovation (strip to brick, full rewire, full replumb), moving out is strongly advisable — the dust, noise, loss of kitchen and bathroom facilities, and active building site conditions make occupation impractical and potentially unsafe. For a moderate renovation or an extension, many owners stay in partial occupation, usually phasing the works room by room. Loft conversions are almost always liveable — the main disruption is scaffold and noise, with the staircase installation causing the most significant single-day disruption to the existing house.

What is a party wall notice and how long does it take?

A party wall notice is a legal requirement under the Party Wall etc. Act 1996 whenever building work affects a shared boundary wall, an external wall on the boundary, or an excavation within 3–6 metres of a neighbour's foundations. You must serve at least 2 months' notice before starting structural works (1 month for some types of work). If your neighbour consents in writing, the process is complete. If they don't respond or dissent, both parties appoint (or share) a party wall surveyor, who produces an Award — this typically adds 4–8 weeks. Factor party wall notices into your programme from the start; a forgotten notice can halt works once they've begun.

How accurate is this timeline tool?

This tool provides realistic indicative ranges based on our direct experience delivering projects across London. Actual timelines vary depending on planning authority response times in your borough, the availability of your chosen contractor, the speed of design decision-making, structural discoveries on site, and a range of other factors. Use this as a planning framework, not a contract programme. Only your architect and contractor, with full knowledge of your site and local authority, can produce a reliable project-specific programme.

By My Local London Builder Team · Last updated May 2026 · Timescales are indicative ranges based on London market experience · Individual projects vary.