Paved patio and lawn beside a white rendered house with large sliding glass doors, and a black pergola over garden furniture

HA7 · Stanmore · Harrow

Planning and building regulation drawings in Stanmore (HA7)

Stanmore's housing reflects building from the 18th century into the early 20th rather than a single era. On Stanmore Hill, Georgian and Victorian cottages stand among grand detached villas high on the hillside. Old Church Lane, with its medieval origins around the old church of 1632, carries substantial period houses in mature wooded plots. Dennis Lane and Green Lane are two more of the district's streets.

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London Borough of Harrow granted 83% of 894 householder applications
Drawings in about 7 days

For a homeowner in either conservation area, the practical picture is a period house with a protected setting and, often, mature trees. The Stanmore Hill and Old Church Lane conservation areas are both recorded, and Harrow has made Article 4 directions across its Stanmore conservation areas. Those directions remove permitted development for front-facing changes such as windows, doors, roofs and boundary walls, so work that would be permitted elsewhere can need a planning application where it changes the design or materials. Roof enlargements, side extensions and rear extensions of more than one storey are not permitted development in a conservation area, whether or not an Article 4 direction exists.

In those areas a project therefore turns on three things: the front elevation, the roof and the trees. A rear extension to a villa may sit out of public view, but any part of a design that shows from the lane is weighed against the conservation area, and the wooded hillside plots are likely to carry preserved trees that fix where foundations can go. Before drawing an extension, loft or conversion in Stanmore we confirm which conservation area applies and whether the Article 4 direction reaches your frontage.

Planning in Stanmore: what to know before you apply

Harrow's approach to Stanmore is built around its conservation areas and the character of front elevations, roofs and boundary treatments. Where an Article 4 direction applies, changes that are normally permitted, such as replacing windows, altering a door or changing a boundary wall, need a planning application like any other proposal. Applications on wooded plots should show how trees are protected, and listed or period neighbours may bring added attention. Elsewhere the council applies its HMO Article 4 direction in designated wards, and flats have no householder permitted development at all, so a period house converted into flats needs an application for any external alteration that materially changes its appearance.

Applications are decided by London Borough of Harrow — its planning pages.

Check your route

Does your Stanmore project need planning permission?

Route check · Stanmore (HA7)

ProjectProperty

Listed building?

Conservation area?

Likely permitted development — no planning applicationNeeds checking

A single-storey rear extension up to 4 m deep on a detached house, or 3 m on any other house, is Class A permitted development subject to the height and materials conditions.
An Article 4 direction applies here and may withdraw this freedom — the schedule must be checked before relying on it.
One or more constraints are unknown — we check the council's registers as part of the free appraisal.
Where permitted development applies, a lawful development certificate proves it for lenders and buyers.

Sources: GPDO 2015, Schedule 2, Part 1 · Planning Portal — common projects · Building Regulations 2010 — when approval is needed

This is a first-pass indication from the national rules, not planning advice for your property. Your council's registers, any Article 4 schedule and the exact dimensions decide it — the free appraisal checks all three before we recommend a route.

Confirm it with a free appraisal

Stanmore (HA7) in numbers

What London Borough of Harrow has decided, and what HA7 is built of — the two facts that shape every job here.

Householder planning decisions — London Borough of Harrow

Stanmore (HA7) applications are decided by London Borough of Harrow; these are its published householder figures for the last four quarters.

Householder applications decided2025 Q2 to 2026 Q1	894
Granted	739
Refused	155
Grantedof 894 decisions · England 90%	83%
Decided within 8 weeksof 677, excluding prior approvals	94%

Source: Ministry of Housing, Communities and Local Government (PS2 district planning application statistics). Open Government Licence v3.0 Extracted 2026-09-22.

Permitted development prior approvals — London Borough of Harrow

How the larger-home-extension route has fared with London Borough of Harrow, which decides HA7 notifications.

Larger home extension prior approvals — not required2024 Q2 to 2026 Q1	617
Prior approval granted	47
Prior approval refused	171
Grantedof 218 determined	22%

Source: Ministry of Housing, Communities and Local Government (PS1 district planning application statistics). Open Government Licence v3.0 Extracted 2026-09-22.

Planning appeals — London Borough of Harrow

Refusals in HA7 can be appealed to the Planning Inspectorate; this is London Borough of Harrow's householder appeal record.

Householder appeals determined2021–2026	319
Allowed	135
Allowedof 319 · England 36%	42%

Source: Planning Inspectorate appeals casework. Open Government Licence v3.0 Extracted 2026-09-22.

Conservation areas and Article 4 directions — London Borough of Harrow

Register counts for London Borough of Harrow. A count describes what the council has published, never a rank against another council.

Conservation areas in the register	27

Source: MHCLG Planning Data Platform. Open Government Licence v3.0 Extracted 2026-09-22.

What HA7 is built of

Residential building form across Stanmore (HA7), from 131 classified buildings — the fact that decides party walls, side returns and loft headroom before any policy does.

Attached on more than one side	27%
Attached on one side	55%
Detached	18%
Median building footprint	78 m²
Addresses per buildingAbove about 2 means flats and maisonettes dominate	1.63
Buildings classified	131

Source: Ordnance Survey National Geographic Database (derived statistics). Contains OS data © Crown copyright and database right 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026. Extracted 2026-09-22.

Day 0Measured survey of your Stanmore property — or your existing plans if you have them.
About 7 daysDrawings issued for your approval. Free redraws until you are happy.
SubmissionWe validate against London Borough of Harrow’s checklist and submit on your behalf.
Council: 8-week targetHouseholder applications carry an 8-week statutory target. London Borough of Harrow decided 94% of 677 recent householder applications inside it.

Source: Ministry of Housing, Communities and Local Government (PS2 district planning application statistics). Open Government Licence v3.0 Extracted 2026-09-22.

Neighbourhoods

Streets and neighbourhoods in HA7

Stanmore18th- to early-20th-century

Nearby

Nearby postcode districts

Pinner HA5Canons Park HA8Wealdstone HA3Wembley Park HA9Rayners Lane HA2Sudbury HA0Harrow on the Hill HA1

FAQ

Stanmore (HA7) — FAQs

Can I replace the windows on my Stanmore Hill house without permission?+

Not if the new windows differ from the old ones and the Article 4 direction covers the frontage. Street-facing windows are one of the changes the direction brings under control. A like-for-like repair is not development, but a new window in a different style or material can need an application.

Do I need to worry about trees on a Stanmore plot?+

Yes. The wooded hillside plots are likely to include protected trees, and root zones can limit how close an extension can be built. A tree survey early in the design saves redrawing later.

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