City of London's most space-efficient loft solution when PD-route dormers are blocked. Our chartered team designs mansards that get approved in City of London conservation areas — with heritage statements and planning officer negotiation built in.
City of London's most space-efficient loft solution when PD-route dormers are blocked. Our chartered team designs mansards that get approved in City of London conservation areas — with heritage statements and planning officer negotiation built in.
Housing stock in City of London: Very limited residential — Barbican Estate (listed post-war), Golden Lane Estate, modern luxury flats; overwhelmingly commercial.
Character: Overwhelmingly commercial; residential planning extremely constrained; listed building density the highest of any London borough.
Article 4: Multiple Article 4 Directions around office-to-residential, demolition, and shopfront changes.
We check against City of London Corporation's mansard design guide and design to match the terrace.
Required for City of London's conservation areas — demonstrates the mansard respects character and townscape.
Accurate photomontage showing how the mansard sits alongside neighbours — often decisive at City of London Corporation committee.
Mansards invariably trigger Party Wall notices in City of London's dense terraced streets. Structural package includes new ridge, tie beams, floor joists.
Full liaison with City of London Corporation planning officer, committee representation if called in.
Part L thermal, Part B fire (critical on mansards), Part E acoustic separation.
Single planning or regs submission.
Planning + building regs + structural.
Listed, conservation, complex sites.
Direct answers to the questions City of London homeowners ask every week about mansard roof extensions.
Start a free quote →Mansards in City of London are less common historically — City of London Corporation considers each application on its merits. Rear mansards on suitable terraced or semi-detached properties, matching the roofscape, have a reasonable approval rate with the right design and supporting heritage commentary where relevant.
A 70° front slope is typical for City of London mansards — steep enough to maximise floor area while reading as a roof rather than a full additional storey. Front dormers should be small and symmetrical. City of London Corporation's design guide (where published) takes precedence on detail.
Often yes, but City of London Corporation favours applications supported by wider street precedents. Where mansards already exist nearby in City of London, approval is far more likely. We review street precedents at the feasibility stage.
Our architectural fees for a City of London mansard start at £1,575 (planning + building regs + structural + heritage statement). Typical City of London build costs are £90,000–£150,000 depending on size, complexity and access.
Full-height — typically 2.3–2.5m ceiling from the new floor. Unlike a dormer, which gives partial head height, a mansard provides a complete additional storey within City of London's very limited residential — Barbican Estate (listed post-war), Golden Lane Estate, modern luxury flats terraced context.
We cover all City of London postcodes — {postcodes} — and have submitted mansard applications across the borough. Our heritage statement and design-and-access statement are included in every mansard package.
City of London's very limited residential — Barbican Estate (listed post-war), Golden Lane Estate, modern luxury flats terraced stock is the natural context for mansard extensions — they were originally designed for Victorian and Edwardian rows. Feasibility depends on street precedent, conservation area status and party wall implications. We assess all three at the free site visit.
A mansard adds a full upper storey — typically 35–45m² of usable floor space. In City of London this often converts a 3-bed house to 4 or 5 beds. The steep front slope (70°) and flat top read as a roof, not a full floor, which is why City of London Corporation accepts them more readily than a simple box extension.
We cover every London borough with the same fixed-fee approach. If your property sits on a boundary, here are the neighbouring options.
We cover every architectural technology service in City of London with one chartered team.
From £840. A fixed-fee, end-to-end service — measured survey, scaled drawings, Design & Access Statement where required, Planning P...
From £840. A construction-ready drawing package compliant with every Approved Document — Part A structure, Part B fire, Part L ther...
From £1,225. Every loft type across every City of London roof line — dormer, mansard, hip-to-gable, L-shape, Velux. LDC or full plann...
From £1,225. The whole spectrum — rear extensions, side returns, wraparounds, double-storey, basement digs. Planning-led design with ...
From £995. Turn your unused City of London garage into a bedroom, home office or open-plan kitchen-diner. Planning route assessment...
From £1,950. Full architectural technology service for basement digs and cellar conversions in City of London — structural underpinni...
From £350. Chartered structural engineer calculations for every residential intervention in City of London — steel beams, lintels, ...
From £540. Fixed-fee measured surveys across City of London from £540 — floor plans, elevations and sections to ±3mm accuracy. Leic...
From £450. End-to-end Party Wall Act 1996 service for City of London — Section 1, 3 and 6 notices, schedule of condition surveys, p...
From £1,225. London's most popular loft type — the full-width rear dormer. Planning or Permitted Development route assessed for your ...
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Free quote in 60 seconds. Fixed fee from £1,575. MCIAT chartered.
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