How Long Does a Loft Conversion Take in Greenwich?
Week-by-Week Guide

Spot scaffolding going up on one of the Georgian terraces running off Royal Hill or on a Victorian street between Greenwich town centre and Blackheath, and the question arrives without fail: how long is that entire process going to take when it's my turn? It's the single most common thing Greenwich homeowners want to understand before they commit - and the figure they're given is almost always shorter than reality.

Most on-site loft conversions in Greenwich take 6–10 weeks to build. But the genuine end-to-end timeline - from your first survey call to receiving a completion certificate - sits closer to 3–5 months once design work, Royal Borough of Greenwich planning decisions, and building regulations are all properly accounted for. The pre-build phase absorbs most of that calendar, and it's the stage that receives the least explanation in initial conversations with contractors.

This guide puts that right. Whether your property is a Georgian or early Victorian terrace in SE10, a mid-Victorian semi in Westcombe Park, or a 1930s house near Kidbrooke, here's what happens at every stage - week by week.

How much does a loft conversion cost in Greenwich? → Full cost guide

How Long Does a Loft Conversion Take in Greenwich? The Real Breakdown

On-site build times for loft conversions in Greenwich range from 4 to 14 weeks, with conversion type as the primary variable. What makes Greenwich particularly complex - and interesting - from a loft conversion standpoint is the sheer breadth and age range of its housing stock. The streets closest to the town centre, the Park, and the riverside are among the oldest residential fabric in South East London: Georgian and Regency terraces, early Victorian rows, and Italianate semis, many of which sit within or immediately adjacent to the Greenwich World Heritage Site buffer zone. Further south through Westcombe Park, Kidbrooke, and Lee, the stock transitions into late Victorian semis and 1930s houses with hipped rooflines, where hip-to-gable conversions become the dominant choice.

Understanding which conversion type your property's roof structure and planning context allows is the first and most consequential conversation at survey stage - it determines your build programme and whether you need a full planning application before a single drawing is produced.

According to a 2025 Checkatrade Home Improvement Report, loft conversion enquiries across South East London rose by more than 25% year-on-year. In Greenwich - a postcode that combines international heritage status with strong rail connectivity into central London - the demand for additional space without leaving the area is consistently high.

Here's how build times compare across the conversion types most relevant to Greenwich properties:

For Greenwich's Georgian and early Victorian terraces in SE10 - the rows along Royal Hill, Croom's Hill, Nevada Street, and the grid of streets between the High Road and Maze Hill - the rear dormer is the most viable and popular conversion type, sitting firmly in the 6–8 week build window. In Westcombe Park and Kidbrooke's 1930s stock, the hip-to-gable runs 8–10 weeks. The build is only one part of the total picture - and in Greenwich, the pre-build phase carries more weight than almost anywhere else in South East London.

Why the Total Timeline Is Longer Than the Build: The Pre-Build Phase

What consistently catches Greenwich homeowners off guard is the realisation that the on-site build is actually the shorter half of the total project. Before scaffolding appears outside your home, the project works through three distinct pre-build stages - design, planning, and building regulations - and in Greenwich, that window takes anywhere from 6 to 16 weeks. For properties within the borough's extensive conservation area network, it can run longer still.

Here is what each stage involves:

Design and structural survey (weeks 1–3): An architect or loft conversion specialist surveys your loft, takes detailed measurements, and produces technical drawings. A structural engineer then provides load calculations and steelwork specifications. Allow 2–4 weeks from instruction to completed drawings ready for submission.

Permitted Development or full planning permission? Many Greenwich loft conversions qualify under Permitted Development rights - the volume limits are 40m³ for terraced properties and 50m³ for semi-detached and detached homes (gov.uk Planning Portal, 2026). Even where PD applies, a Lawful Development Certificate (LDC) is strongly recommended - it takes 6–8 weeks from the Royal Borough of Greenwich and is the essential protection when you come to sell.

Where full planning permission is required, Royal Borough of Greenwich targets an 8-week decision for standard applications, though complex cases involving heritage considerations routinely take longer.

Building regulations: Your contractor submits a Full Plans application to the Royal Borough of Greenwich's Building Control team or an approved private inspector. Initial plan review takes 3–5 weeks (royalgreenwich.gov.uk, 2026). Building Control inspections then run alongside the build at key structural and fire-safety milestones throughout.

Planning permission for a loft conversion in Greenwich → Full planning guide

Week 1: Pre-Build Preparation (Quiet from the Pavement - Not Quiet on Site)

To anyone walking past, Week 1 looks unremarkable. The reality is considerably busier. Scaffolding goes up on Day 1 or 2 - and on Greenwich's narrow Georgian and Victorian streets, particularly around Croom's Hill, Nevada Street, and the roads close to the Cutty Sark, this requires advance coordination. Skip permits, temporary traffic management, and phased materials deliveries are often necessary on the tightest residential streets in SE10. On the wider roads through Westcombe Park and Kidbrooke, access is more straightforward.

Materials are staged across this week: structural steels, fresh timber, insulation, and roofing materials. Your contractor forms a secured access point in the roof - a controlled opening that lets materials and crew move between the roof level and loft interior without any impact on the living spaces below. At this stage, everything happens above the ceiling line.

Your pre-Week 1 preparation checklist:

• Completely clear the loft space - roof access and a clean void are essential before steelwork begins
• Lay dust sheets over floors and furniture in the rooms directly below the build zone
• Confirm skip placement and delivery logistics with your contractor well in advance - skip permits on Greenwich's heritage streets can take several working days to process through the council
• Inform immediate neighbours before scaffolding goes up - on the tightly packed Georgian terraces around Greenwich town centre and Royal Hill, this courtesy prevents friction and keeps relations smooth throughout the build

Weeks 2–4: Structural Work and Shell (The Noisy Phase)

Weeks 2–4 are when the build announces itself to the neighbourhood. Steel beams go in, the existing floor structure is upgraded, and the dormer or gable shell starts to appear above the roofline. The activity is loud and generates vibration through the upper structure - but it is firmly contained above the ceiling line throughout, well clear of the habitable rooms below.

Week 2 - Structural work:

• Existing floor joists assessed and strengthened, or a new structural floor built from the ground up
• Steel RSJ beams installed to manage load transfer (Greenwich's Georgian and early Victorian properties often carry complex structural arrangements - multiple chimney stacks, shallow roof pitches, and long-span joist arrangements that all influence steel specification)
• Roof partially opened at the dormer position

Week 3 - Dormer or gable frame:

• Timber dormer frame constructed, positioned, and fixed
• Flat or pitched dormer roof formed depending on design and planning consent
• Roof made temporarily weatherproof at the close of each working day - non-negotiable practice, particularly in a maritime climate exposed to Thames weather patterns

Week 4 - Weatherproofing and glazing:

• Dormer cladding applied - on conservation area and World Heritage Site-adjacent properties, material choices are strictly governed: matching natural Welsh slate, reclaimed London stock brick, or lead are the typical requirements; render and concrete tile are rarely accepted by Greenwich planners
• Windows and Velux units installed and fully sealed
• Roof made permanently watertight - this triggers the next Building Control inspection

Weeks 5–6: First Fix - The Build Moves Indoors

With the shell permanently watertight, the build moves almost entirely inside. For the household below, this is the most comfortable phase - the impact noise of structural work gives way to the steadier, quieter activity of insulation, boarding, and first-fix services running through the loft space.

What first fix covers:

• Thermal insulation installed to roof, walls, and floor - meeting Building Regulations Part L, updated in 2026 with tighter thermal performance thresholds that are particularly relevant to older, solid-wall properties common in SE10
• Internal stud partition walls formed to define the room layout and any en-suite zone
• First fix electrics: all cabling routed and run before boarding begins
• First fix plumbing where an en-suite is included - adds approximately 3–5 working days to the phase
• Fire separation work throughout the building: mains-wired interlinked smoke alarms required on every storey under Part B of the Building Regulations

Building Control mid-build inspection: The Royal Borough of Greenwich's Building Control team carries out a scheduled inspection at first fix stage - structural drawings should be readily available on-site. Greenwich Building Control accommodates video inspections for lower-risk elements such as insulation fit and joist spacing, which reduces the time lost coordinating physical site visits (royalgreenwich.gov.uk, 2026).

Weeks 7–9: Staircase, Plastering, and Second Fix

The staircase installation is the single most disruptive day of the entire build. The landing ceiling below is opened just enough to lower the new flight in and secure it - first-floor landing access is restricted for most of that working day. From the following morning, disruption to the household falls away sharply.

With the staircase in and secured, second fix picks up pace:

Week 7–8 - Plastering:
Plasterboard is fixed to all walls and the ceiling, followed by a finish skim coat. The transformation at this stage is dramatic - the structural shell becomes a recognisable room. Allow 3–5 full days for the plaster to cure before any decoration starts. Painting over inadequately dried plaster is the single most avoidable cause of hairline cracking that homeowners mistake for a structural defect. It is purely a patience issue.

Week 8–9 - Second fix:

• Sockets, switches, and light fittings wired, connected, and tested
• En-suite bathroom fixtures installed and plumbed where included
• Floor covering fitted - engineered oak, LVT, or carpet (your preference must be confirmed with Buildaway before this week, not on the day the flooring contractor arrives)
• Joinery completed: skirtings, architraves, door linings, fitted eaves storage where specified in the design

Adding an en-suite bathroom extends this phase by approximately 3–5 working days. It is consistently one of the most financially rewarding decisions in the build programme. Nationwide's 2026 House Price Index research found that a loft conversion delivering a double bedroom and bathroom can lift a three-bedroom property's value by up to 24% - and in Greenwich's SE10 postcode, where property prices reflect both the heritage premium and the proximity to Canary Wharf and the City, that percentage uplift represents a particularly compelling absolute return.

Week 9–10: Final Inspection and Your Completion Certificate

The final Building Control inspection is the last formal gate before your new room is legally habitable. In Greenwich, this is carried out by either the Royal Borough of Greenwich's Building Control team or a private approved inspector - Buildaway coordinates the scheduling and attendance throughout the project.

What the inspector checks at this stage:

• Structural integrity of the new floor, roof structure, and all internal partition walls
• Full fire safety compliance: door ratings, smoke alarm positions and interconnection, fire separation between all floors
• Staircase compliance - head height clearance at the pitch line, rise and going dimensions, handrail specification
• Thermal insulation confirming Part L compliance, including continuity at junctions
• Electrical installation certificate from your Part P registered electrician

On sign-off, the inspector issues your completion certificate. This document has concrete financial and legal value - your solicitor will request it when the property is sold, and your mortgage lender may require it if you remortgage after the conversion. Store it alongside your LDC, planning consent, and any Historic England correspondence from the design stage.

Most Greenwich homeowners decorate after handover - either directly themselves or through a local decorator. Buildaway can recommend trusted decorators experienced in working within SE10's period properties if that is useful.

Can You Stay in Your Home During a Loft Conversion in Greenwich?

Yes - in the vast majority of cases. Loft conversions are designed to be lived around, and the process on a Georgian or Victorian terrace in SE10 is no different from any other property type in that respect. The structural phase in Weeks 2–4 is the noisiest, but the entire activity stays above the ceiling line throughout. The staircase installation day is the sole moment where the existing living space is genuinely affected - and it is typically resolved within a single working day.

Preparation is what separates a manageable experience from a stressful one. Clear the loft entirely before Day 1, put dust sheets down over furniture and floors in the rooms below, and agree working hours with your contractor at the outset. Most Greenwich contractors work 8am–5pm Monday to Friday. On streets within the conservation area and close to the town centre, Saturday working is typically limited or avoided to respect residential amenity - your contractor will confirm this before the programme is agreed.

The Key Takeaways for Greenwich Homeowners

Getting a loft conversion right in Greenwich requires a more thorough understanding of the planning landscape than most other London postcodes. Here is what to hold onto:

• On-site build time is 6–10 weeks for most SE10 and SE3 property types. The full programme including pre-build is 3–5 months - longer on conservation area and World Heritage zone properties where planning decisions take more time.
• Greenwich's conservation area and World Heritage Site designations are the defining planning consideration in this postcode. Check your exact address status before assuming Permitted Development applies. The consequences of proceeding without the correct consent on a heritage-sensitive property are serious.
• Material specifications matter here more than anywhere else in South East London. Natural slate, reclaimed brick, lead - Greenwich planners and Historic England consultees have clear expectations, and departing from them risks refusal or costly remediation.
• Shallow roof pitches on pre-1870 properties need checking at survey. A Velux conversion is often the only structurally and planning-viable option on the oldest Georgian stock - discovering this after a full planning application has been submitted is an expensive mistake.
• An en-suite adds 3–5 days and up to 24% property value uplift. Nationwide's 2026 data makes the financial case clearly. Include it from the start.
• The completion certificate is a legal document, not a formality. Store it alongside your LDC, planning consent, and any Historic England correspondence - your solicitor will need the full set at point of sale.

Buildaway's free loft survey covers all of Greenwich's SE10 postcode - including the town centre, Royal Hill, Maze Hill, Westcombe Park, and Croom's Hill - as well as SE3 Blackheath, SE7 Charlton, and SE18 Woolwich.