Table of Contents
- How much does a loft conversion cost in Greenwich?
- Add-ons to budget for
- What's included in those prices (and what isn't)
- What drives loft conversion cost up — or down
- Planning permission & building regulations in Greenwich
- Timeline: how long does a loft conversion take?
- ROI: how much value can a loft conversion add in Greenwich?
- How to choose the right loft conversion company in Greenwich
- Budget-smart tips (without cutting corners)
- Example Buildaway packages (guide pricing)
- FAQs (Greenwich)
- Why Greenwich homeowners choose Buildaway
Greenwich (SE10) is one of London's most historic and desirable areas, famous for the Royal Observatory, Greenwich Park, the Cutty Sark, and the Maritime World Heritage Site. Alongside its rich heritage and bustling riverside culture, Greenwich is also a highly practical place to live — with excellent schools, the University of Greenwich, and fast DLR and rail links into central London. Properties range from Victorian terraces and Georgian townhouses to 1930s semis and modern riverside apartments. Many of these homes, especially terraces and period properties, are perfect candidates for loft conversions to gain valuable extra space in this sought-after location.
Running out of room in Greenwich? A loft conversion can turn unused roof space into a stylish and practical new living area — whether it's a double bedroom, en-suite, or home office — while boosting property value significantly. This Greenwich-specific guide outlines accurate 2025 price ranges, what's included, what influences cost, planning and regulations, timelines, ROI potential, and how to choose the right builder.
How much does a loft conversion cost in Greenwich?
Pricing below reflects South East London / Greenwich market rates for 2025 (labour + materials), with insulation, structural works, and compliant finishes included.
| Conversion Type | Typical Total Range (2025) | Best For | What You Typically Get |
|---|---|---|---|
| Velux / Rooflight | £25,000 – £35,000+ | Quick, cost-effective extra room | Joists, steels, insulation, 1–2 rooflights, plaster finish, electrics, heating tie-in |
| Rear Dormer (most popular) | £35,000 – £55,000+ | Full-height bedroom + en-suite | Everything in Velux plus dormer structure, cladding, staircase, more usable floorspace and daylight |
| Hip-to-Gable (with or without dormer) | £50,000 – £65,000+ | 1930s semis and end-terraces in Greenwich | Extend hip to gable, extra steels, larger space; often paired with a dormer |
| Mansard | £60,000 – £80,000+ | Victorian terraces / conservation areas | Roof rebuild, mansard walls/windows, superior insulation, bespoke staircase, maximum floorspace and headroom |
Add-ons to budget for:
- En-suite fit-out: £4,000 – £8,000+
- Juliet balcony / feature glazing: £2,000 – £6,000+
- Bespoke staircase & joinery: £1,500 – £4,000+
What's included in those prices (and what isn't)
Included:
- Measured survey, structural calcs, Building Control liaison
- New steels, joists, and floor deck
- Roof alterations (Velux, dormer, hip-to-gable, or mansard)
- Thermal/acoustic insulation to Part L
- Fire safety upgrades (alarms, FD30 doors, escape windows)
- Electrics, heating, and radiators
- Plaster finish and basic joinery
- Timber staircase compliant with Part K
- Building Control inspections & certification
Exclusions:
- Bathroom sanitaryware and tiling
- Premium designer finishes (bespoke wardrobes, crittall glazing)
- Planning application and Party Wall surveyor fees
- Full re-roofing outside loft works
- Full decorating beyond basic paint
What drives loft conversion cost up — or down
Cost drivers (increase costs):
- Mansards and complex roof rebuilds
- Older Greenwich terraces needing significant steelwork
- Bespoke staircase layouts in period houses
- Bathrooms/en-suites with premium tiling and upgraded plumbing
- Juliet balconies or large feature glazing
- Conservation restrictions near Greenwich Park and World Heritage zones
- Difficult site access or parking restrictions in central Greenwich streets
Ways to control costs:
- Stay within Permitted Development limits
- Place bathrooms above existing plumbing stacks
- Choose standard staircase layouts
- Focus spend on insulation, airtightness, and visible finishes
Planning permission & building regulations in Greenwich
Permitted Development (PD): Most Velux and many dormers qualify, subject to volume/material limits.
Planning permission: Needed for mansards, front dormers, or properties near Greenwich Park and World Heritage conservation zones.
Party Wall etc. Act 1996: Applies to most terraced/semis in SE10; budget £1,000–£2,000+ per neighbour.
Building Regulations:
- Part A – structure
- Part B – fire safety (escape windows, alarms, fire doors)
- Part K – staircase pitch/headroom
- Part L – insulation/thermal efficiency
- Part P – electrical certification
- Ventilation for en-suites/wet rooms
Timeline: how long does a loft conversion take?
- Pre-construction (design + approvals): 3–8 weeks
- Velux build: 4–6 weeks
- Rear Dormer: 6–8 weeks
- Hip-to-Gable / Mansard: 8–12+ weeks
- Snagging & sign-off: 1–2 weeks
ROI: how much value can a loft conversion add in Greenwich?
Adding a loft conversion in Greenwich typically increases property value by 10–20%. With strong demand from families and professionals wanting to live close to transport, schools, and riverside amenities, an extra bedroom or en-suite is a major selling point.
How to choose the right loft conversion company in Greenwich
- Full-service: design, structure, build, and finishes
- Transparent, itemised pricing
- Compliance with Building Control and certificates for electrics/fire safety
- 18-month Buildaway workmanship warranty
- Proven local experience across SE10 projects
- Skilled in working within conservation and heritage-sensitive areas
Budget-smart tips (without cutting corners)
- Plan headroom early in period terraces
- Fix staircase layout at design stage
- Stack plumbing above existing services
- Spend on insulation and energy efficiency
- Upgrade visible finishes like glazing, lighting, and brassware
Example Buildaway packages (guide pricing)
- Velux Room-in-Roof — £27,500–£34,500
Includes floor structure, insulation, rooflights, staircase, electrics/heating, plaster finish. En-suite prep optional. - Rear Dormer + En-suite Ready — £42,000–£56,000
Includes dormer, staircase, insulation upgrades, M&E, plaster finish. En-suite fit-out +£4,000–£8,000. - Hip-to-Gable with Rear Dormer — £54,000–£68,000
Includes hip-to-gable extension, steels, dormer, staircase, full compliance, plaster finish.
(All guide prices include labour, materials, waste disposal, and Building Control. Final quotes vary by survey, access, and specification.)
FAQs (Greenwich)
Do I need planning permission?
Often no for Velux/rear dormers under PD; yes for mansards, front dormers, or conservation-sensitive areas.
Can I add an en-suite?
Yes — usually £4,000–£8,000+.
Will my roof need strengthening?
Yes, most Greenwich properties require new steels and joists.
Can we live at home during the build?
Yes, with dust/noise; security and weatherproofing are maintained.
How do you handle fire safety?
Linked alarms, FD30 doors, compliant escape routes per Part B.
What warranty do you provide?
Buildaway provides an 18-month workmanship warranty.
Why Greenwich homeowners choose Buildaway
Local experience across SE10, Westcombe Park, and Deptford borders.
Full Building Regulations and Party Wall compliance.
Transparent, line-item pricing with no hidden extras.
Skilled in-house team delivering end-to-end service.
18-month workmanship warranty and aftercare.
High-quality materials and finishes for a lasting investment.