Hillingdon's most space-efficient loft solution when PD-route dormers are blocked. Our chartered team designs mansards that get approved in Hillingdon conservation areas — with heritage statements and planning officer negotiation built in.
Hillingdon's most space-efficient loft solution when PD-route dormers are blocked. Our chartered team designs mansards that get approved in Hillingdon conservation areas — with heritage statements and planning officer negotiation built in.
Housing stock in Hillingdon: 1930s semi-detached dominates; Metropolitan Green Belt covers much of north Hillingdon; Victorian cottages in Uxbridge and Ruislip villages; post-war housing near Heathrow.
Character: Largest outer west London borough; significant Green Belt; Heathrow noise contours affect planning decisions in Harmondsworth and Sipson.
We check against Hillingdon Council's mansard design guide and design to match the terrace.
Required for Hillingdon's conservation areas — demonstrates the mansard respects character and townscape.
Accurate photomontage showing how the mansard sits alongside neighbours — often decisive at Hillingdon Council committee.
Mansards invariably trigger Party Wall notices in Hillingdon's dense terraced streets. Structural package includes new ridge, tie beams, floor joists.
Full liaison with Hillingdon Council 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 Hillingdon homeowners ask every week about mansard roof extensions.
Start a free quote →Mansards in Hillingdon are less common historically — Hillingdon Council 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 Hillingdon 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. Hillingdon Council's design guide (where published) takes precedence on detail.
Often yes, but Hillingdon Council favours applications supported by wider street precedents. Where mansards already exist nearby in Hillingdon, approval is far more likely. We review street precedents at the feasibility stage.
Our architectural fees for a Hillingdon mansard start at £1,575 (planning + building regs + structural + heritage statement). Typical Hillingdon 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 Hillingdon's 1930s semi-detached dominates terraced context.
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 Hillingdon 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 {location} roof line — dormer, mansard, hip-to-gable, L-shape, Velux. LDC or full planning ...
From £1,225. The whole spectrum — rear extensions, side returns, wraparounds, double-storey, basement digs. Planning-led design with ...
From £995. Turn your unused {location} garage into a bedroom, home office or open-plan kitchen-diner. Planning route assessment, fu...
From £1,950. Full architectural technology service for basement digs and cellar conversions in {location} — structural underpinning d...
From £350. Chartered structural engineer calculations for every residential intervention in {location} — steel beams, lintels, pad ...
From £450. End-to-end Party Wall Act 1996 service for {location} — Section 1, 3 and 6 notices, schedule of condition surveys, party...
From £1,225. London's most popular loft type — the full-width rear dormer. Planning or Permitted Development route assessed for your ...
Free quote in 60 seconds. Fixed fee from £1,575. MCIAT chartered.
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