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Harrow, London

Prior approval drawings in Harrow

Prior approval drawings for a Harrow house are the plans and elevations that go with a larger home extension notification, and in Harrow most of those notifications fail. In the latest year of returns it refused 108 notifications and granted 27. We draw to meet the objections behind that record, or advise a different route. Fixed quote after a free constraints check.

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    Architectural model of a four-storey London stucco townhouse in its terrace, with a portico, area railings, sash windows, a cornice and chimney stacks
    The house as it stands: four storeys over a lower ground floor.Existing Proposed worksAn illustrative model, built for this page.

    How we work on prior approval drawings

    Seven steps from first call to approval.

    The same model cut through the middle: every floor, the stair, the chimney breasts, the new mansard, rear extension and basement in section
    Section through the model: every floor on one datum.

    1. Enquiry and constraints check

      We check the property against conservation areas, listed status, Article 4 directions, tree preservation orders, flood zone and planning history. We choose the right route and send a fixed quote.

    2. Measured survey

      We survey the house on one datum: rooms, levels, boundaries, drains, trees and the neighbours' windows that the 45° and 25° tests depend on.

    3. Design options

      We model the house in Revit and show you options in 3D and plan, with the planning strategy and the precedents in your street.

    4. Design frozen

      You choose an option in writing. Nothing changes after this without your say.

    5. Independent check

      A second chartered technologist checks every sheet against the council's validation checklist and the policy. A senior review signs it off before anything is submitted.

    6. Submission

      We prepare the forms, certificates, fee and documents and submit through the Planning Portal.

    7. Officer liaison

      We answer the planning officer and make any amendments within five working days, at no charge until approval.

    Free redraws until approval. Every drawing set is checked independently, and the checker is never the person who drew it.

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    What Harrow's refusal record means for your extension

    The council's latest government returns show 27 larger home extension prior approvals granted and 108 refused. Refusals far outnumber consents. A route that most owners treat as a formality is, in this borough, a test that most submissions fail, and an owner should know that before paying for any drawings.

    A volume of refusals like this normally means one of two things: the council reads the neighbour test strictly, or many notifications arrive incomplete or at the full permitted depth with no attempt to reduce the impact. We cannot say which from the returns alone, so we plan for both. The national limits we draw to are: 6 m (attached) / 8 m (detached), single storey, height max 4 m; not on article 2(3) land or an SSSI. The council has 42 days from a valid notification.

    With 0 additional-storey notifications granted and 0 refused, the Class AA route is unused, and a roof-raising proposal needs a full application.

    Rows of brick terraced houses and gardens on a residential street

    Local figures for Harrow

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Larger home extension prior approvals granted27 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Larger home extension prior approvals refused108 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Upward home extension prior approvals granted0 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Conservation areas31 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries295 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Green Belt share of the council area22 % of council area covered by green-belt polygons—planning.data.gov.uk
    Households living in a house65.4 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Owner-occupied households58.8 % of households owner-occupied (owned outright or with mortgage/loan)Census 2021nomisweb.co.uk
    Domestic gardens share of land (GLUD 2005)34.7 % of land that is domestic garden (GLUD 2005)2005data.london.gov.uk
    Householder applications granted81.7 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Lawful development certificate applications (PS1)461 certificates2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Class A, para A.1(g)6 m (attached) / 8 m (detached), single storey, height max 4 m; not on article 2(3) land or an SSSI—legislation.gov.uk
    Class A, para A.4(10)(c): development may begin if the LPA has not notified a decision within 42 days of receiving the information42 days—legislation.gov.uk
    Prior approval: Larger Home Extensions Part 1 Class A; Additional storeys Part 1 Class AA249 GBP—ribblevalley.gov.uk

    A blank value means the figure has not been published, not that there are none. Check your own address with the council.

    Councils bordering Harrow
    Which application your project needsLawful Development Certificate decision: 8 weeks. Prior approval decision: 42 days. Householder decision: 8 weeksYour projectWithin permitted development?Lawful Development CertificatePrior approvalHouseholder applicationYesLarger rear extensionNoABC

    Which application your project needs

    The usual route for a house; flats and listed buildings follow other rules.

    A · Lawful Development Certificate decision
    8 weeks
    B · Prior approval decision
    42 days
    C · Householder decision
    8 weeks

    The suburban houses that suit this route

    65.4% of Harrow households live in a house, and 58.8% own their home. Domestic gardens cover about 34.7% of the borough's land in the national land-use dataset, so there is room to extend: semi-detached houses on deep plots are exactly what the larger home rights were written for.

    A semi sold for £663,954 on average on the latest Land Registry figures and a terrace for £536,748. The extra space is worth the effort of a careful notification, which is why a high refusal count in Harrow is a reason to prepare better, not to give up.

    Green Belt, conservation areas and listed buildings

    22% of the borough is Green Belt, the council publishes 31 conservation areas, and there are 295 listed building entries. Prior approval does not apply a Green Belt test, but a refusal sends you to a householder application, where openness would be weighed. A conservation area excludes the notification route altogether.

    We check the plot against the council's published boundaries and report the result in the free constraints check. If the route is closed, our planning drawings service covers the householder application.

    Drawing a Harrow notification beyond the minimum

    The Order lists the information to supply: Written description (depth beyond rear wall, max height, eaves height), site plan, addresses of adjoining premises, developer contact address. In a borough with this record we treat the list as a minimum. We add a section through the nearest neighbour's window, a rear elevation that shows the eaves against the boundary, and a short written note on levels, because a sloping garden can change how tall an extension looks from next door.

    The site plan is prepared as in our location and block plans service. The council fee is £249, paid to the council, and our own fee is fixed after the free check. A second chartered architectural technologist (MCIAT) checks the set, and we answer any officer query promptly.

    What a notification looks like when it succeeds

    Not every Harrow notification fails, and the successful ones share features that we can copy. The depth is measured correctly from the original rear wall, the eaves are shown against the boundary, the neighbour's windows are drawn and dimensioned, and the extension stays comfortably inside the limit rather than touching it. An officer who can confirm all of that from the sheets has little left to refuse.

    We therefore treat the limit as a ceiling to approach with care, not a target. If the design works a short distance inside it, we usually recommend that, because the same space can be won with a lower risk of the council reading the neighbour test against you. Where a Harrow plot backs onto Green Belt land or a conservation area boundary, we also mark that edge on the site plan, so the officer can see at a glance that the house itself sits outside it.

    Costs, timing and the second route

    A prior approval notification is cheaper than a householder application on the council side and quicker when it succeeds. When it fails the cost is time, and in a borough with Harrow's record we put that in the quote conversation openly. Our fixed fee covers the notification, any amendment the council asks for.

    We will not recommend a route simply because it is the cheaper one for us to draw. If the survey shows a neighbour's window facing the flank wall, we tell you the notification is a poor bet and explain what the householder route would involve instead.

    Ordinary applications and certificates as the alternative

    Harrow decided 917 householder applications in its latest year and granted 81.7% of them, with 93.7% decided in time. For many Harrow owners that is the better route, even when prior approval is open, because the officer weighs the whole design.

    Where an extension fits ordinary limits, a Lawful Development Certificate gives firm proof; the council decided 461 of them. Brent and Hillingdon border the borough with different records, and our Harrow area page lists every service we offer here.

    What you receive

    Planning drawing sheet for a rear extension with plans, elevations and sections
    Sample drawing. Planning drawings for a rear extension: plans, elevations and sections on one sheet set.
    Georgian brick terrace with sash windows, arched fanlight doorways, stone steps and iron railings in London
    The street around you
    Move across the plinth — the blocks rise around the pointer.

    Other services in Harrow

    Prior approval drawings nearby

    Questions

    Why does Harrow refuse so many larger home extensions?

    The returns show 108 refused against 27 granted. They do not give reasons, so we draw to answer neighbour impact in full.

    Does Green Belt block prior approval in Harrow?

    Not directly, but 22% of the borough is Green Belt and a refusal leads to an application where openness counts.

    How long does the council have?

    42 days from a valid notification. We cannot promise a decision date.

    What is the council fee?

    £249, paid to the council. Our fee is fixed after the free check.

    Sources and dates

    City of London skyline glowing at dusk across the Thames under a dramatic orange sky

    Tell us about your property.

    We check the constraints, then send a fixed fee. Messages before 3pm get a reply the same working day.

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