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Hillingdon, London

Prior approval drawings in Hillingdon

Prior approval drawings for a Hillingdon house support a larger home extension notification, and Hillingdon grants most of what it decides: 29 granted against 13 refused in the latest year of returns. The catch is the map, with 150 Article 4 directions and 42% Green Belt. Fixed quote after a free constraints check.

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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    Georgian brick terrace with sash windows, arched fanlight doorways, stone steps and iron railings in London

    Hillingdon grants more than it refuses

    The council's latest government returns show 29 larger home extension prior approvals granted and 13 refused. Consents outnumber refusals by a clear margin, so a clean notification on a suitable house has a good chance of succeeding in this borough, whatever else the figures cannot show.

    We read that record carefully but do not rely on it. The Order's limits are: 6 m (attached) / 8 m (detached), single storey, height max 4 m; not on article 2(3) land or an SSSI, and the council has 42 days from a valid notification. Additional-storey notifications are absent, with 0 granted and 0 refused, so we do not recommend that route here.

    Brick cottage with a tiled roof, chimneys and a front dormer window

    Local figures for Hillingdon

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Larger home extension prior approvals granted29 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Larger home extension prior approvals refused13 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Article 4 directions150 Article 4 directions published by the council—planning.data.gov.uk
    Conservation areas33 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries436 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Green Belt share of the council area42 % of council area covered by green-belt polygons—planning.data.gov.uk
    Households living in a house68.9 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Owner-occupied households56.6 % of households owner-occupied (owned outright or with mortgage/loan)Census 2021nomisweb.co.uk
    Average price, semi-detached583,573 GBP2026-07publicdata.landregistry.gov.uk
    Householder applications granted90.2 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Lawful development certificate applications (PS1)529 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 Hillingdon
    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 Article 4 map that decides who can use the route

    Hillingdon has published 150 Article 4 directions, along with 33 conservation areas and 436 listed building entries. A direction can remove a permitted development right across an estate or a street, and the larger home extension route sits on top of that right.

    For an owner the lesson is that a neighbour's successful notification is not evidence for yours. Two houses on the same road can fall either side of a direction boundary. We check each plot against the council's published polygons and report the result in writing in the free constraints check. If the right has been withdrawn, a householder application is needed instead, which our planning drawings service covers.

    Metroland semis and the Green Belt edge

    68.9% of Hillingdon households live in a house and 56.6% own their home. A suburban semi with a reasonable plot suits a rear extension well. A semi averaged £583,573 on the latest Land Registry figures and a terrace £457,686.

    42% of the borough is Green Belt. The notification route does not apply a Green Belt test, but a refusal would send you to an application where openness is judged, so for houses near the Green Belt boundary we show you the fallback before you commit.

    What the notification contains

    The Order asks for: Written description (depth beyond rear wall, max height, eaves height), site plan, addresses of adjoining premises, developer contact address. We prepare that and add scaled plans, a rear elevation and a section through the nearest neighbouring window, with the site plan prepared as in our location and block plans service.

    A neighbour's conservatory or garage may stand close to the boundary. We record it, because an extension beside a blank flank wall is a very different proposition from one beside a habitable window. The council fee is £249, paid to the council, and our fee is fixed after the free check.

    Householder applications and certificates compared

    The council decided 1,147 householder applications in its latest year and granted 90.2% of them, with 94.3% decided in time. It also decided 529 Lawful Development Certificates, and for an extension inside ordinary limits a Lawful Development Certificate is the simpler proof.

    Harrow to the east has a very different notification record from Hillingdon, and Hounslow to the south has a different one again. Our Hillingdon area page lists everything else we offer in the borough.

    Reading a neighbour's notification against your own

    It is common for an owner to point to a street extension and say that it was approved, so theirs should be. Sometimes that is a fair guide, and sometimes it is not: the neighbour's house may have been a different type, the Article 4 direction boundary may run between you, or the earlier work may have used a different route such as a certificate. We look up the council's published records for nearby addresses and tell you which comparisons hold.

    If the council's online register shows a similar notification close by, we read the decision notice and any officer comments. That tells us how the officer weighed the neighbour test in practice on your street, which is better evidence than any borough-wide figure.

    Fees and what happens if the route closes

    The free constraints check carries no obligation. If it shows the route is open, we quote a fixed fee for survey, drawings, checking and submission. If it shows the route is closed, we tell you why, and quote instead for the application that does apply, so you are not paying for work you cannot use.

    Once a notification is submitted the council's own fee is separate and due to the council. If the council asks for amendments, we make them within five working days and do not charge a second time for the drawing work.

    Our process on a Hillingdon house

    The free constraints check reports on building type, designations and fit with the Order. A fixed fee follows, then a measured survey of the house and the adjoining rear elevations, then design options if the neighbour test is close. A second chartered architectural technologist (MCIAT) checks the finished set before we submit.

    We track the neighbour period and answer officer questions, and if the council asks for amendments we redraw them without charging again. The route is only as good as the file behind it, and we write ours so that an officer does not need to visit to understand it.

    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.
    Rear view of brick terraced houses in London with slate roofs and chimney stacks along the shared roofline
    The street around you
    Move across the plinth — the blocks rise around the pointer.

    Other services in Hillingdon

    Prior approval drawings nearby

    Questions

    Does Hillingdon grant larger home extension notifications?

    In the latest published year it granted 29 and refused 13.

    How do Article 4 directions affect me?

    Hillingdon has published 150. A direction can remove the permitted development right, so we check your plot before quoting.

    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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