L-shaped wraparound drawings for Harrow — a full-width rear extension married to the side-return infill so the whole ground floor opens up, drawn to Harrow Council's guidance, delivered in days and revised free until your decision, with a free approval-odds check first.
Harrow Council granted 83% of the householder planning decisions it made in its latest published year — 4 points below the 87% England-wide householder average. Hip-to-gable conversions dominate because so much of the stock is hipped 1930s semis — roof bulk and the pair's balance are the tests, which is where a policy-literate drawing pack earns its keep. Its dominant Edwardian (1901–1910) and interwar (1918–1939) housing stock sets the design brief on most streets.
The permitted-development ceilings are fixed: 40m³ of new roof volume for a terraced loft and 50m³ for a semi or detached house under Class B, plus a 3m single-storey rear extension on a terrace or 4m on a detached house under Class A. Harrow carries at least one Article 4 direction, and conservation areas including Harrow on the Hill, Pinner High Street and Pinner Village remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Harrow is determined against an 8-week statutory target.
Harrow on the Hill (historic hilltop conservation area), Pinner (the medieval High Street and Metroland semis), Stanmore (detached and semi-detached interwar houses), Wealdstone (Edwardian terraces near the town centre), Rayners Lane (classic Metroland semi-detached estates) and Kenton (1930s hipped-roof semis) — these are the Harrow pockets our drawings cover most. Heritage designations here include Harrow on the Hill, Pinner High Street, Pinner Village, Roxeth and Harrow Weald. Harrow Council weighs each proposal against Harrow Local Plan and the Residential Design Guide SPD, where the borough resists loss of the gaps between semis that define Metroland streets. On roofs the borough is hipped roofs on the 1930s semis and steeper gabled roofs in Pinner village, over interwar Metroland semi-detached houses, Edwardian terraces around the stations and detached homes on the hill.
A wraparound is the ambitious ground-floor move, and Harrow has the stock that suits it — the borough is built largely from interwar Metroland semi-detached houses, Edwardian terraces around the stations and detached homes on the hill, and the terraces and semis with an L-shaped back addition give you both a side alley to infill and a rear garden to project into. Do both in one L-shaped sweep and the kitchen, dining and living space merge into a single room that runs the full width of the house and out into the garden. Harrow Council assesses the scheme against Harrow Local Plan and the Residential Design Guide SPD, and because the footprint is large it looks hardest at what survives of the garden.
The drawings carry the argument. We show the retained private amenity space to scale, prove the rear projection sits within the depth the council accepts for the house type, and set the side leg so it clears the boundary and keeps the neighbour's daylight — a wraparound touches two boundaries, not one, so both neighbour relationships are drawn out. Hip-to-gable conversions dominate because so much of the stock is hipped 1930s semis — roof bulk and the pair's balance are the tests, which on a footprint this size is where a scheme is won or lost.
Where Harrow's streets sit in conservation areas — Harrow on the Hill, Pinner High Street, Pinner Village, Roxeth and Harrow Weald among them — a wraparound is never permitted development and the design is read against the area's character. Harrow on the Hill and the Pinner conservation areas carry tight controls, and several streets have Article 4 directions removing permitted-development rights. We settle the designation before the footprint is fixed.
A wraparound in Harrow almost always needs a full householder application, because joining a side infill to a deep rear extension takes it past permitted-development limits. You will need to apply to Harrow Council if any of these apply — and for a true wraparound, at least one always will:
We draw the L-shaped footprint against the retained garden, the rear depth within the council's limit for your house type and the two neighbour boundaries the side and rear legs touch — the things Harrow Council's officers and both neighbours check — then submit a validation-complete householder application.
Below is Harrow Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Harrow grants a fair share of householder applications, with hip-to-gable roof bulk on Metroland semis and the spacing between paired houses the recurring considerations. A wraparound stands or falls on the garden it leaves and the two boundaries it meets, so a pack that settles both upfront is decided faster and refused less often than a DIY submission.
Source: MHCLG planning application statistics (householder decisions, rolling year). Compare every borough on our London approval-rate league table.
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Across Harrow on the Hill, Pinner and Stanmore, the approved wraparound is a single-storey L that reads as one considered addition rather than two bolted together: the rear leg kept to the depth the council accepts, the side leg matched to the host brick and roofed with a glazed flat or lantern, and enough garden left to satisfy the borough's private-amenity expectation. On the borough's interwar metroland semi-detached houses, this is the biggest transformation the ground floor can take in a single application.
The borough resists loss of the gaps between semis that define Metroland streets. We size the footprint so the garden that remains still works, keep the eaves and roof low enough to protect both neighbours' light, and present the whole L as a single scheme — which reads far more clearly to Harrow Council than a side return and a rear extension submitted as separate, overlapping proposals.
We draw L-shaped wraparounds on the terraced and semi-detached streets across the borough. A few of the neighbourhoods where Harrow wraparounds come up most often:
Wraparound extension drawings for Harrow on the Hill's historic hilltop conservation area — garden-checked, boundary-detailed and drawn to Harrow Council's guidance.
Wraparound extension drawings for Pinner's the medieval High Street and Metroland semis — garden-checked, boundary-detailed and drawn to Harrow Council's guidance.
Wraparound extension drawings for Stanmore's detached and semi-detached interwar houses — garden-checked, boundary-detailed and drawn to Harrow Council's guidance.
Wraparound extension drawings for Wealdstone's Edwardian terraces near the town centre — garden-checked, boundary-detailed and drawn to Harrow Council's guidance.
Wraparound extension drawings for Rayners Lane's classic Metroland semi-detached estates — garden-checked, boundary-detailed and drawn to Harrow Council's guidance.
Wraparound extension drawings for Kenton's 1930s hipped-roof semis — garden-checked, boundary-detailed and drawn to Harrow Council's guidance.
A wraparound is the two smaller extensions combined — which changes what Harrow Council needs and what the ground floor gains. This is how the options compare.
| Ground-floor option | Permitted development? | What it gains | What Harrow Council checks |
|---|---|---|---|
| Side return only | Sometimes, within width and height limits | Full-width kitchen | Width, roof glazing |
| Rear extension only | Often, within the depth limit | Deeper living space | Rear depth, neighbour daylight |
| Wraparound (side + rear) | No — full application | Largest open-plan ground floor | Combined footprint, garden retained |
| Two-storey wraparound | No — full application | Room above as well as below | Bulk, overlooking, two boundaries |
In conservation areas such as Harrow on the Hill and Pinner High Street, a wraparound is never permitted development and always needs a full application.
A fixed process built around how Harrow Council validates and decides wraparound applications — most drawings are submission-ready within seven days of survey.
Send us your Harrow postcode and house type. We confirm your conservation and Article 4 status, measure the garden against the borough's amenity expectation, and score your odds against live Harrow Council decisions.
We measure the side alley, the rear building line, the garden depth and both neighbours' window heights — the numbers the footprint, rear depth and two-boundary daylight tests depend on.
Chartered designers develop the L-shaped extension to your brief, drawn to Harrow Council's extension guidance with the retained garden, rear depth and both boundary junctions detailed on the page.
We submit the householder application, manage validation and case-officer queries, and revise the drawings free until Harrow Council issues its decision.
Almost always. A wraparound joins a side-return infill to a rear extension, and that combination takes the footprint past what permitted development allows, so it needs a full householder application to Harrow Council. Only the rare, very shallow case stays within the limits. On designated land — a conservation area such as Harrow on the Hill and Pinner High Street — a wraparound is never permitted development, so an application is certain.
It is an L-shaped extension that fills the side return and wraps around into a full-width rear extension in one continuous sweep, so the kitchen, dining and living space become a single open room the width of the house. Harrow's period terraces and semis with an L-shaped back addition suit it well, which is why the wraparound is the borough's biggest single-storey extension. Harrow Council is the decision-maker.
Harrow Council expects a usable amount of private garden to survive, because a wraparound is the deepest single-storey footprint and takes the most outdoor space. There is no single fixed figure — it is judged on the plot and the borough's amenity guidance — so we draw the retained garden to scale and size the extension around it, rather than maximising the build and hoping it passes.
Usually on both sides. A wraparound touches two boundaries — the side leg runs along one neighbour and the rear leg can affect the other — so the Party Wall etc. Act often applies to each, and notice must be served before work starts. This is separate from Harrow Council's planning decision. We detail both boundary junctions on the drawings and flag the notices early so surveyors can be appointed without delaying the build.
Built as one project it usually is, and it reads better to Harrow Council too. A single wraparound application covers the whole L-shaped footprint in one decision rather than two overlapping submissions, and the build shares one set of foundations, one roof and one disruption. We draw it as a single coherent scheme so the council assesses one clear proposal instead of piecing two together.
We price each Harrow wraparound individually, because garden depth, side-alley width and roof form vary house to house, and send a fixed, no-obligation quote within one working day. It covers the full drawing pack with free revisions until Harrow Council approves, and we confirm the retained-garden and boundary position at the outset. Call 020 7864 7245 to start.
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