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Free 2026 London Planning Report — Mansard Loft Conversion Drawings in Northolt UB5

Rear garden extension on a 1930s semi-detached home in Northolt UB5
Northolt · UB5 · Ealing

Mansard Loft Conversion Drawings in Northolt UB5

Fixed-fee, MCIAT-chartered mansard loft conversion drawings for Northolt (UB5) homeowners — London Borough of Ealing validation and local constraints handled from the start.

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In Northolt (UB5) we prepare planning and building-control drawings for rear extensions, loft conversions and garage conversions on the district's 1930s semis and interwar homes.

Around the Northolt Village Green conservation area we check the boundary and the setting of nearby heritage buildings first, then advise whether your extension runs as permitted development or needs a full application.

Rear garden extension on a 1930s semi-detached home in Northolt UB5
Isometric illustration of a Northolt UB5 home mansard loft conversion drawings design
Proposed floor plan
Northolt UB5

Planning in Northolt (UB5): what to know before you apply

The bulk of 1930s UB5 housing sits outside the small Village Green conservation area and keeps full permitted-development rights for rear extensions and lofts. Plots near the green face conservation-area control on demolition, side extensions and anything affecting the historic setting.

Typical Northolt housing stock

Northolt centres on the historic Village Green around St Mary's Church and Court Farm Road, but the wider UB5 district is predominantly 1930s semi-detached and interwar suburban housing with good-sized rear gardens.

Streets we regularly draw for in Northolt

Ealing Road · Court Farm Road · Church Road · Islip Manor Road

Mansard Loft Conversion Drawings for Northolt (UB5) homes: the package and the process

Every mansard loft conversion drawings we prepare for an Northolt property is drawn to London Borough of Ealing’s validation standards and tuned to the UB5 constraints above. Here is what the drawing package covers and how the process runs from first survey to approval.

A mansard loft conversion replaces the existing rear roof slope with a new, steeply pitched structure that runs almost to the vertical, set behind a shallow flat section at the ridge. It is the most involved of the three main loft types because it is effectively a new roof, not an addition to the old one — but it also delivers the most usable floor area and headroom, and it is the type most London terraces were designed to carry in the first place.

DrawingsDirect draws mansards for period terraces across every London borough. Because a mansard alters the whole roof form, we treat the planning application as the main event — matching slate or tile colour, window rhythm and eaves detailing to the host building and its neighbours — while coordinating the structural design, Party Wall Act notices and building regulations drawings in parallel so nothing holds up the build once consent is granted.

What is a mansard loft conversion?

A mansard replaces the rear roof slope — or, less commonly, the front and rear slopes together — with a new near-vertical wall rising from the party walls to a shallow flat roof at the ridge, with small dormer windows set into it. Unlike a dormer, which sits within the existing roof, a mansard changes the shape of the roof itself, which is why it is usually reserved for terraces where the extra headroom and floor area are worth the more involved planning and construction process. Because the new wall runs almost the full width of the house between the party walls, a mansard typically delivers noticeably more usable floor area than a single dormer of any kind, which is why it remains the preferred option on period terraces where every square metre of loft counts.

Does a mansard loft conversion need planning permission in London?

Yes, almost always. Permitted development rights for roof alterations are volume- and shape-limited, and a mansard goes well beyond what those limits allow because it materially alters the roof's profile rather than adding to it. Every mansard we draw is prepared as a full householder planning application, with a design and access statement where the borough requires one, so the council can properly assess the change to the roofline and its impact on neighbours and the street scene.

Typical mansard loft conversion drawing packages
PackageScopePlanning routeFee from
Rear mansard, planning onlyDesign, planning drawings and supporting statementHouseholder planning£1,600
Rear mansard, planning and building regsPlanning drawings plus structural and Part L detailingHouseholder planning£2,200
Front and rear mansardFull roof rebuild on both slopes, with structuralHouseholder planning£2,400

Also in Northolt UB5

Planning PermissionPlanning DrawingsArchitectural DrawingsBuilding Regulations DrawingsLoft Conversion DrawingsMansard Loft Conversion Drawings across EalingMansard Loft Conversion Drawings across London
FAQ

Mansard Loft Conversion Drawings in Northolt UB5 — FAQs

How much do mansard loft conversion drawings cost in London?+
Planning drawings for a rear mansard typically start around £1,600. A combined planning and building regulations package, or a front-and-rear mansard, usually runs to around £2,200–£2,400 once structural calculations are included.
Can a mansard ever be permitted development?+
Rarely — because it changes the shape of the roof rather than adding within it, a mansard almost always exceeds permitted development tolerances. If you want to avoid a full application, ask us whether a dormer or hip-to-gable conversion would meet your space needs instead.
How long do mansard drawings take?+
A full planning drawing set is typically ready within about 10–14 days of survey, reflecting the extra design and consultation work a full roof rebuild involves. The statutory 8-week householder determination period then runs from validation.
Will a mansard need scaffolding and affect the whole roof?+
Yes — because the existing rear roof slope is removed and rebuilt, a mansard is a larger construction project than a dormer, and we design the sequencing and structural tie-ins with that in mind so your builder can programme the work efficiently.
Do you handle the party wall process as well as the drawings?+
We identify which neighbours require notice under the Party Wall etc. Act 1996 and provide the drawings needed to support the notice, so the party wall and planning processes can run in parallel rather than one waiting on the other.
Do I need planning permission for a rear extension in Ealing?+
Many Ealing semis and terraces keep permitted development rights for a single-storey rear extension, so a full application isn't always needed. But the borough-wide Article 4 direction on HMO conversions, and conservation areas such as Bedford Park and Pitshanger, remove or restrict those rights in places. We check your address against the designations first and, where it qualifies, confirm permitted development with a Lawful Development Certificate.
What extra control applies in Bedford Park?+
Bedford Park is one of West London's most tightly controlled conservation areas, with detailed control over materials, rooflines, windows and front elevations. A standard permitted-development dormer or cladding change usually won't apply; instead we design to the area's Arts-and-Crafts character and prepare a full householder application with the elevations and materials the council expects — the reliable route to approval there.
How long does Ealing Council take to decide a householder application?+
Ealing determines most householder applications within the statutory eight-week period once they are validated. The commonest cause of delay is a validation query over missing or inconsistent drawings, so we prepare Ealing submissions to the council's validation checklist — correctly scaled existing and proposed plans, elevations and a location plan — to avoid that back-and-forth.
Can you help with a loft conversion on a 1930s Ealing semi?+
Yes. Ealing's Metro-land semis in Perivale, Greenford and Northolt suit hip-to-gable and dormer loft conversions, which frequently qualify as permitted development on semi-detached homes within the volume limits. We confirm eligibility against those limits and any Article 4 or conservation constraint, then produce the planning and building-regulations drawings.
How much do planning drawings cost in Ealing?+
We work to a fixed fee agreed before we start, typically around 30% below an architect's charge for the same council-accepted drawings, with free redraws until Ealing grants approval. The exact figure depends on the project — a single-storey rear extension differs from a double-storey or a loft — so we quote once we understand your scheme rather than on an open-ended hourly basis.
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