Wraparound Extension Drawings in North Harrow and Rayners Lane HA2
Fixed-fee, MCIAT-chartered wraparound extension drawings for North Harrow and Rayners Lane (HA2) homeowners — London Borough of Harrow validation and local constraints handled from the start.
HA2 covers North Harrow, Rayners Lane, West Harrow and Roxeth — largely a Metro-land suburb of 1920s and 1930s semis where rear extensions, loft conversions and side infills are the everyday projects. The uniform inter-war house type means Harrow's design expectations for extensions are well understood across most of the district.
Two genuine conservation areas sit inside HA2: Roxeth Hill (designated 1969), a historic village pocket at the foot of Harrow Hill, and Rayners Lane (designated 2002), which protects the Charles Holden station and the Art Deco parades on Alexandra Avenue. We confirm which side of those boundaries a property falls on before advising.
Planning in North Harrow and Rayners Lane (HA2): what to know before you apply
Most inter-war semis in HA2 retain permitted-development rights for rear and loft work, so many projects avoid a full application. The exceptions are the Roxeth Hill and Rayners Lane conservation areas, where roofline, front-elevation and material changes face tighter control and a householder application is usually needed.
Typical North Harrow and Rayners Lane housing stock
Mostly 1920s-30s Metro-land semis and terraces around North Harrow and Rayners Lane, with an older, tighter grain of historic buildings surviving on Roxeth Hill at the foot of the hill.
Streets we regularly draw for in North Harrow and Rayners Lane
Roxeth Hill · West Hill · Alexandra Avenue · Rayners Lane · Imperial Drive
Wraparound Extension Drawings for North Harrow and Rayners Lane (HA2) homes: the package and the process
Every wraparound extension drawings we prepare for an North Harrow and Rayners Lane property is drawn to London Borough of Harrow’s validation standards and tuned to the HA2 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.
| Route | What it covers | Typical fee |
|---|---|---|
| Full planning permission | Required for almost all wraparound extensions given the combined footprint | Full Planning pack ~£1,600–£2,400 |
| Planning + Building Regulations (structural) | Combined pack including structural calculations for the L-shaped frame and drainage diversion | Planning + Building Regs pack ~£2,200–£3,850 |
| Rear extension alone (comparison) | Smaller single-storey addition, may qualify for permitted development | see Rear Extension Drawings, from £1,100 |
| Side return alone (comparison) | Widens the kitchen only, keeps garden depth unchanged | see Side Return Extension Drawings, from £1,400 |
Wraparound Extension Drawings in North Harrow and Rayners Lane HA2 — FAQs
How much does a wraparound extension cost to design in London?+
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Can I extend a home in Harrow on the Hill or Pinner?+
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