Loft Conversion Specialists · London
Loft conversions, done properly, across London.
Dormer, mansard, hip-to-gable and Velux loft conversions. Designed, built and signed off by a London team that does this work every week.
Honest pricing. Fixed programmes. Clean sites.
Building Control sign-off included
Party wall & planning handled
All London boroughs
Why Mayfair Interiors
A London builder that actually finishes the work and signs it off.
Most homeowners we meet have been let down by someone before. A builder who under-quoted to win the job and disappeared halfway through. A "specialist" who managed nothing on site. A project that ran six months late and £30,000 over.
We work differently. Every loft conversion we deliver runs to a fixed programme, with one project manager from survey to handover, and Building Control sign-off included as standard. We're a London team — we know how Victorian terraces, semi-detached houses, end-of-terrace gables and mansion-block conversions actually behave when you start opening them up.
From SW Wandsworth to N Islington, from Wimbledon to Walthamstow — we work across all 32 London boroughs.
Four ways to convert a London loft
Which one is right for your home?
London's housing stock is unusually varied — Victorian terraces, Edwardian semis, mid-century blocks, mansion blocks. The right loft conversion depends on your roof, your floor plan, and what you want from the space.
01 — Dormer
Most common London loft conversion
A box-shaped extension that protrudes from the rear roof slope, creating full head height and usable floor space. The default choice for most Victorian and Edwardian London terraces — often permitted development, often the best value per square foot.
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From £45,000
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On site 10–12 weeks
03 — Hip-to-Gable
Semi-detached & end-of-terrace
A sloped side roof is converted into a vertical gable wall, adding significant internal volume. Often combined with a rear dormer for end-of-terrace and semi-detached homes — common across outer London.
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From £50,000
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On site 12–14 weeks
02 — Mansard
Maximum space, period-correct
The entire rear roof is rebuilt to a near-vertical slope, with a slight pitch and a flat top — maximising internal floor area. Common in central London terraces and conservation areas where mansards are the planning-approved choice.
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From £55,000
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On site 12–16 weeks
04 — Velux / Rooflight
Minimal change, fastest delivery
The simplest conversion — internal works only, with rooflight windows installed into the existing roof slope. Best for lofts that already have generous head height. Usually permitted development; the quickest to deliver.
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From £25,000
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On site 6–8 weeks
WHAT'S INCLUDED
A complete loft conversion.
Not just the building work.
Our quotes include everything you need to move into your finished loft. No mid-project surprises, no scope gaps you didn't know to ask about.
London cost guide
Honest pricing.
No surprises.
"The lowest quote is almost never the cheapest project.
We price what the work actually costs to do properly, and we tell you why."
Conversion type
Typical London cost
What it adds
On-Site
Velux / Rooflight
From £25,000
Spare room, study or extra light
6–8 weeks
Dormer
From £45,000
Double bedroom and ensuite
8–14 weeks
Hip to gable
From £50,000
Full-width master suite
12–14 weeks
Mansard
From £55,000
A whole new floor
12–16 weeks
Four ways to convert a London loft
A London builder that actually finishes the work and signs it off.
Most homeowners we meet have been let down by someone before. A builder who under-quoted to win the job and disappeared halfway through. A "specialist" who managed nothing on site. A project that ran six months late and £30,000 over.
We work differently. Every loft conversion we deliver runs to a fixed programme, with one project manager from survey to handover, and Building Control sign-off included as standard. We're a London team — we know how Victorian terraces, semi-detached houses, end-of-terrace gables and mansion-block conversions actually behave when you start opening them up.
From SW Wandsworth to N Islington, from Wimbledon to Walthamstow — we work across all 32 London boroughs.
How it works
From first survey to final certificate
1
Free survey
We visit, measure up and talk through what is possible for your roof.
2
Design & quote
Drawings, a fixed price and a fixed programme. No vague estimates.
3
Consents
Planning, structural sign-off and party wall matters, all managed by us.
4
Build
Scaffold up, roof opened, room built. Clean site, controlled dust and noise.
5
Sign-off
Building Control completion certificate and a finished room ready to use.
Compliance & safety
As Principal Contractor, we take full responsibility for compliance and safety. We produce RAMS, coordinate trades, and maintain protection for building users throughout. Every project is delivered in line with CDM 2015 and HSE best practice.
Examples Of Our Work
A full suite of services, delivered seamlessly to keep projects on time, on budget, and without disruption.
FAQ about loft conversions
Ready to add a room to your home?
Book a free, no-obligation site survey. We will tell you what is possible, what it will cost and how long it will take, before you commit to anything.