Mansard Roof Extensions · W11 Notting Hill
Fixed-fee mansard roof extensions for Notting Hill, Holland Park, Ladbroke Grove, Portobello in the W11 postcode, drawn by an MCIAT-chartered architectural technologist and submitted to RBKC Planning. W11 lies almost entirely within Kensington & Chelsea conservation areas, with many listed terraces and communal gardens under detailed control.
MCIAT chartered drawings for planning, building regs, lofts and extensions — fixed fees 30% below typical London architects. Tell us what you need and we’ll reply the same working day.
A mansard roof extension adds a full storey behind a new sloping front face — a strong option on W11's terraces in Notting Hill where a standard dormer is too small. RBKC Planning scrutinises mansards on townscape and precedent, especially within Ladbroke, Norland, Pembridge, Portobello; we design to the borough's roof guidance with a Heritage Statement where the setting requires it.
Notting Hill's most space-efficient loft solution when PD-route dormers are blocked. Our chartered team designs mansards that get approved in Notting Hill conservation areas — with heritage statements and planning officer negotiation built in.
Across Notting Hill, Holland Park, Ladbroke Grove, Portobello in W11, the dominant property is grand victorian stucco-fronted terraces and garden-square houses across notting hill and holland park, with mews houses and mansion flats. That stock shapes what mansard roof extensions looks like here: the right approach for a period terrace differs from a mansion-block flat or a new-build, and RBKC Planning judges each on design quality and neighbour impact. We survey the specific Notting Hill property, confirm the planning route — Permitted Development, a Lawful Development Certificate, or full planning — and draw a council-ready set tailored to the W11 streetscape.
Housing stock in W11: Grand Victorian stucco-fronted terraces and garden-square houses across Notting Hill and Holland Park, with mews houses and mansion flats.
Within the district: Notting Hill, Holland Park, Ladbroke Grove, Portobello.
Streets we know in W11: the Ladbroke Estate communal-garden squares, Lansdowne Road, Elgin Crescent and the Portland Road mews. Each road has its own building line, boundary treatment and precedent that RBKC Planning weighs when assessing a mansard roof extensions scheme.
Conservation areas: Ladbroke, Norland, Pembridge, Portobello. Inside these, most external work needs full planning and a Heritage Statement.
Getting around W11: Notting Hill Gate, Holland Park and Ladbroke Grove on the Central, District and Circle lines.
Property values: around £1m for a flat and £3m+ for a garden-square house — a useful gauge of the build value an extension or loft adds in W11.
Borough character: Internationally wealthy residents; extensive listed building coverage; heritage and streetscape prioritised in every decision.
We check against RBKC Planning's mansard design guide and design to match the terrace.
Required for Notting Hill's conservation areas — demonstrates the mansard respects character and townscape.
Accurate photomontage showing how the mansard sits alongside neighbours — often decisive at RBKC Planning committee.
Mansards invariably trigger Party Wall notices in Notting Hill's dense terraced streets. Structural package includes new ridge, tie beams, floor joists.
Full liaison with RBKC Planning planning officer, committee representation if called in.
Part L thermal, Part B fire (critical on mansards), Part E acoustic separation.
Single planning or building-regs submission.
Planning + building regs + structural.
Listed, conservation or complex sites.
Heavily. The Ladbroke, Norland and Pembridge conservation areas, with many listed stucco terraces and communal gardens, mean full planning — and often Listed Building Consent — for external changes, with RBKC scrutinising stucco, railings, sashes and roofscape closely. We design to that standard and produce the heritage documentation required.
Yes, historically, but RBKC's basement policy is among London's strictest — generally single-storey, no extension under more than half the garden, with a full Basement Impact Assessment covering structure, hydrology and trees. The Ladbroke Estate houses can suit a single-storey basement; we draw the scheme and coordinate the engineering reports.
It needs care. The Ladbroke Estate communal-garden squares have both conservation control and garden-committee restrictions, and rear changes are assessed on their impact on the shared garden. We design to RBKC's guidance and the garden's covenants, and serve Party Wall notices where works affect neighbours.
Sometimes. The Portland Road and Pottery Lane mews are still in conservation areas, but their simpler form can allow a roof or rear addition where it doesn't harm the mews character. We assess the specific mews and design within RBKC's policy, advising honestly on what is achievable before you commit.
Our fixed fee for mansard roof extensions in Notting Hill starts at £1,575 — no hourly billing. With Notting Hill property at around £1m for a flat and £3m+ for a garden-square house, the professional drawing fee is a small fraction of the value the work adds to W11's grand victorian stucco-fronted terraces and garden-square houses. RBKC Planning charges its own statutory application fee on top (currently £258 for a householder planning application, £578 for a full application). We quote the drawings as one fixed price and the free site survey covers every W11 address.
For a W11 project across Notting Hill, Holland Park, Ladbroke Grove, Portobello, expect roughly 3–4 weeks from instruction to submission: week 1 the measured survey, weeks 2–3 the drawings and your revisions, then validation and the statutory determination by RBKC Planning (8 weeks for a householder application). We carry the Notting Hill application through every officer query to the decision.
Notting Hill (W11) sits primarily in Kensington and Chelsea, so applications are decided by RBKC Planning. Article 4 in force in the borough: Yes. Conservation areas within W11 include Ladbroke, Norland, Pembridge, Portobello, where full planning and a Heritage Statement are required. We confirm the planning route for your exact address before quoting.
Almost always. Any structural work behind mansard roof extensions in Notting Hill — new openings, steel beams, loft floors, foundations — needs Building Regulations approval covering structure (Part A), fire escape (Part B) and insulation (Part L), submitted to RBKC Planning Building Control or an approved inspector. On W11's typically terraced and semi-detached stock, a Party Wall notice to adjoining neighbours is normally required before the steelwork. We coordinate both as part of the Complete package.
In value terms, yes. With Notting Hill (W11) property at around £1m for a flat and £3m+ for a garden-square house, a well-designed extension or loft typically returns more than it costs in added floor area and sale value, while our fixed drawing fee from £1,575 keeps the professional cost predictable. The bigger risk is an unapproved or non-compliant scheme — which is why council-ready drawings and a clean Building Control sign-off matter on W11 homes.
From £840.
From £840.
From £1,225.
From £1,225.
From £995.
From £1,950.
From £350.
From £540.
From £450.
From £1,225.
Pick a slot that suits you. No obligation and no sales pressure — just straight answers on your planning route, fixed fee and timescale.
Every W11 postcode district we draw in, the stock that dominates it and the authority that validates a mansard roof extension there. W11 fees below are the statutory England rates for 2026, not mansard roof extension estimates.
| Postcode | Area | Dominant stock | What it means for a mansard roof extension |
|---|---|---|---|
| W11 | Notting Hill / Holland Park | Victorian stucco terraces | W11 covers Notting Hill / Holland Park only; RBKC Planning handles the mansard roof extension, and Notting Hill / Holland Park case officers apply the W11 conservation-area map. |
| W11 | Notting Hill | Victorian stucco terraces | Notting Hill sits inside W11; mansard roof extension proposals here are determined by RBKC Planning. |
| W11 | Holland Park | Victorian and Edwardian villas | Holland Park sits inside W11; mansard roof extension proposals here are determined by RBKC Planning. |
| SW3 | Chelsea / Brompton | Georgian and Victorian terraces, listed buildings | Adjoining district to W11, also inside Kensington and Chelsea for mansard roof extension purposes. |
| SW5 | Earl's Court | Stucco terraces, Edwardian mansion blocks | Adjoining district to W11, also inside Kensington and Chelsea for mansard roof extension purposes. |
| SW7 | South Kensington / Knightsbridge | Stucco terraces, mansion blocks, listed buildings | Adjoining district to W11, also inside Kensington and Chelsea for mansard roof extension purposes. |
| SW10 | West Brompton / World's End | Georgian and Victorian terraces, listed buildings | Adjoining district to W11, also inside Kensington and Chelsea for mansard roof extension purposes. |
Roof pitch, wall build-up and plot depth change every few W11 streets, and each one changes what a mansard roof extension can achieve at that address.
Conservation areas covering W11 (Notting Hill / Holland Park): RBKC Planning runs 38, and Chelsea, Notting Hill, Holland Park are the ones W11 (Notting Hill / Holland Park) owners meet most. A mansard roof extension inside a W11 (Notting Hill / Holland Park) conservation area loses permitted development, so the W11 (Notting Hill / Holland Park) submission is a householder application at £258 decided in 8 weeks — not a £120 prior approval decided in 6 weeks. In Chelsea a mansard roof extension is judged on the street elevation first.
Article 4 and your W11 (Notting Hill / Holland Park) mansard roof extension: Article 4 Directions covering HMOs, office-to-residential, and basement developments — RBKC has some of the strictest basement policies in London. At a W11 address that matters twice over, because RBKC Planning applies the direction unevenly across W11 (Notting Hill / Holland Park) — we read the W11 (Notting Hill / Holland Park) policies map for the exact W11 address before quoting mansard roof extensions.
W11 (Notting Hill / Holland Park) below-ground policy: RBKC's basement policy (post-2015) limits to single-storey under 50% of garden area; double-storey basements effectively prohibited in residential streets. Any mansard roof extension in W11 (Notting Hill / Holland Park) that goes below existing foundations triggers two months notice under section 6 of the Party Wall etc. Act 1996, and RBKC Planning will want the W11 ground and groundwater position set out.
The building fabric around W11 (Notting Hill / Holland Park): Grand white stucco Regency and Victorian terraces; red-brick Queen Anne mansions in Kensington; Edwardian mansion blocks; almost no post-war housing stock. Internationally wealthy residents; extensive listed building coverage; heritage and streetscape prioritised in every decision. A mansard roof extension in W11 (Notting Hill / Holland Park) is scoped against that stock first. Our W11 (Notting Hill / Holland Park) fixed fee starts at £1,575; the £1,750 Complete package runs the W11 (Notting Hill / Holland Park) scheme through RBKC Planning planning and building control in one go.
Sources for this W11 mansard roof extension page: borough policies maps and conservation-area registers (2025–26), Royal Mail postcode district boundaries, the Town and Country Planning (Fees for Applications) (England) Regulations, the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended, and the Party Wall etc. Act 1996.
Free fixed quote in 60 seconds. From £1,575. MCIAT chartered.
Get my free quote →Or contact us about your project firstBefore you commit, it is worth understanding fixed fees, 30% below London architects and seeing why work with us. You can find your service to find the right fit, or set up your account to track your project. When you are ready, get a quote for your project — most homeowners have a fee in minutes — or contact us and a chartered technologist will be in touch.
