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Free 2026 London Planning ReportWraparound Extension Drawings in Osterley TW7

Open-plan kitchen extension in a 1930s Osterley TW7 house, architectural drawings for London Borough of Hounslow planning
Osterley · TW7 · Hounslow

Wraparound Extension Drawings in Osterley TW7

Fixed-fee, MCIAT-chartered wraparound extension drawings for Osterley (TW7) homeowners — London Borough of Hounslow validation and local constraints handled from the start.

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Osterley is a green, spacious interwar suburb wrapped around Osterley Park, so the houses here are larger than the west-Hounslow average and the projects follow suit: wide rear extensions, two-storey side additions and generous loft conversions on the semis and detached homes along Jersey Road and Ellington Road. Bigger footprints mean many schemes go past permitted-development volume and land as full householder applications.

Because so much of the district sits within or beside the Osterley Park and Spring Grove conservation areas — and under mature, often protected street trees — we design to Hounslow Council's higher bar here, keeping the scale subordinate, matching brick and fenestration, and coordinating with an arboricultural approach where roots and TPOs affect the foundations.

Open-plan kitchen extension in a 1930s Osterley TW7 house, architectural drawings for London Borough of Hounslow planning
Isometric illustration of a Osterley TW7 home wraparound extension drawings design
Proposed floor plan
Osterley TW7

Planning in Osterley (TW7): what to know before you apply

No published householder Article 4 direction applies in Osterley, but the Osterley Park and Spring Grove conservation areas, the National Trust parkland setting and Tree Preservation Orders on mature street trees all tighten how extension scale, materials and foundations are assessed.

Typical Osterley housing stock

Osterley is a leafy 1920s and 30s suburb of substantial semi-detached and detached houses on generous, tree-lined plots around Osterley Park. Roads like Jersey Road and Ellington Road carry larger family homes that suit full-width rear extensions, two-storey side additions and considered loft conversions.

Streets we regularly draw for in Osterley

Ellington Road · Jersey Road · Alderney Avenue · Addison Avenue

Wraparound Extension Drawings for Osterley (TW7) homes: the package and the process

Every wraparound extension drawings we prepare for an Osterley property is drawn to London Borough of Hounslow’s validation standards and tuned to the TW7 constraints above. Here is what the drawing package covers and how the process runs from first survey to approval.

A wraparound extension is what happens when a rear extension and a side return are designed together rather than as two separate projects: the new build wraps around the back corner of the house, turning a galley kitchen and a small rear room into one continuous kitchen, dining and living space running the full width of the plot. It is the most ambitious single-storey option most London terraces and semi-detached houses have, and because it reshapes almost the entire ground floor, it needs careful structural and drainage planning as well as a confident planning application.

DrawingsDirect draws wraparound extensions for full planning and building regulations, with structural calculations for the L-shaped frame and any drainage diversion produced in-house by our MCIAT-chartered team, on a fixed fee. If your project is a single-storey rear addition or a side infill on its own, see our Rear Extension and Side Return Extension pages; if you also want a second storey, see Double Storey Extension Drawings.

What makes a wraparound extension different from a rear or side return alone?

A rear extension adds depth at the back of the house; a side return adds width down the alley; a wraparound does both at once, so the new floor area turns the corner of the original building rather than sitting against just one wall. The result is typically the largest open-plan space a single-storey extension can deliver, but it also means more of the original external wall is removed and more of the roof is new, which raises the structural and drainage stakes compared with either extension on its own. Homeowners who start out planning a rear extension or a side return alone often move to a wraparound once they see how little extra it costs to combine the two, since much of the groundwork, roof structure and glazing is shared between them rather than duplicated.

Do wraparound extensions need full planning permission in London?

Almost always, yes. Permitted development allowances are calculated on combined additions to the original house, and a wraparound's depth plus width together generally exceed the volume and footprint limits that apply to a rear extension or side extension considered separately. A Lawful Development Certificate route is rarely viable for a genuine wraparound.

Conservation area status and Article 4 directions, common across the terraced streets where wraparound extensions are most popular, remove permitted development rights further still, so we design every wraparound on the assumption it will go through full householder planning.

Wraparound extension planning routes
RouteWhat it coversTypical fee
Full planning permissionRequired for almost all wraparound extensions given the combined footprintFull Planning pack ~£1,600–£2,400
Planning + Building Regulations (structural)Combined pack including structural calculations for the L-shaped frame and drainage diversionPlanning + Building Regs pack ~£2,200–£3,850
Rear extension alone (comparison)Smaller single-storey addition, may qualify for permitted developmentsee Rear Extension Drawings, from £1,100
Side return alone (comparison)Widens the kitchen only, keeps garden depth unchangedsee Side Return Extension Drawings, from £1,400
FAQ

Wraparound Extension Drawings in Osterley TW7 — FAQs

How much does a wraparound extension cost to design in London?+
Wraparound extension drawings start from £2,200, covering full planning permission and structural design for the combined frame. Adding building regulations and construction detail brings the package to the Planning + Building Regs band, up to around £3,850, fixed and agreed upfront.
Does a wraparound extension always need planning permission?+
In almost every case, yes. The combined depth and width of a rear and side return together generally exceed permitted development limits, so we design wraparound projects on the assumption a full householder planning application is needed.
Do I need an architect for a wraparound extension?+
No. DrawingsDirect is an MCIAT-chartered architectural technologist practice, producing the same council-accepted drawings and structural coordination as an architect, for a fixed fee typically around 30% lower, with one team responsible for both the rear and side return elements rather than two separately briefed designers.
Will I need a Party Wall Agreement for a wraparound extension?+
Usually, because the side return element of a wraparound typically builds against or close to the boundary with the neighbouring property. We prepare the drawings your Party Wall surveyor needs alongside the planning application, timed so the notice period runs in parallel with the council's determination rather than adding to your overall timescale.
How long does it take to get wraparound extension drawings?+
Drawings are typically ready around 7 days from survey. A householder planning application then has a statutory 8-week determination period once submitted.
Do I need planning permission for an extension in Hounslow?+
It depends on the area. The interwar semis of Osterley, Hounslow and Feltham often retain permitted development rights for rear extensions and lofts, while the Chiswick terraces and Bedford Park sit within conservation areas where those rights are removed. We check your address against the designations first and can 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.
Does Heathrow or the river affect my Hounslow project?+
They can. Toward the west of the borough, aircraft-noise considerations near Heathrow may influence habitable-room and glazing design, and along the Thames at Strand-on-the-Green and Isleworth the flood zone must be addressed. We evidence these considerations within the application where they apply so the council can validate and approve without repeated revisions.
How long does Hounslow Council take to decide?+
Hounslow determines most householder applications within the statutory eight-week period once validated; Bedford Park, conservation and riverside cases can involve additional consultation. We prepare submissions to the council's validation checklist to avoid the drawing queries that cause most delays.
How much do planning drawings cost in Hounslow?+
We agree a fixed fee before starting, typically around 30% below an architect's fee for the same council-accepted drawings, with free redraws until Hounslow approves. A suburban Osterley extension and a Bedford Park application differ in the evidence required, so we quote once we understand your address and project rather than by the hour.
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