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Hounslow, London

Prior approval drawings in Hounslow

Prior approval drawings for a Hounslow house back a larger home extension notification to a council that refused 59 of them and granted 20 in the latest year of returns. The borough also contains a World Heritage Site and 33 conservation areas, so the route is closed on more land than owners expect. Fixed quote after a free constraints check.

Fixed quote after a free constraints check

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  • LABC Partnered
  • Fixed fees, VAT included

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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

    Hounslow refuses about three notifications for every one it grants

    The latest government returns show 20 larger home extension prior approvals granted and 59 refused in Hounslow. An owner should treat the route as demanding, not routine.

    Additional-storey notifications are almost unused, with 0 granted and 1 refused, so we do not offer that route as a likely option here. The national limits 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.

    A ratio like this has a practical effect on how we work. Where the survey suggests the neighbour test is marginal, we say so at the outset and quote the householder application alongside the notification, so you are never relying on a route the numbers suggest is a coin toss at best.

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

    Local figures for Hounslow

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Larger home extension prior approvals granted20 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Larger home extension prior approvals refused59 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    worldHeritageSites1 World Heritage Sites intersecting the LPA boundary—planning.data.gov.uk
    Conservation areas33 named conservation areas published by the council—planning.data.gov.uk
    Grade I listed entries32 list entries—planning.data.gov.uk
    Article 4 directions3 Article 4 directions published by the council—planning.data.gov.uk
    Households living in a house54 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Average price, terraced611,320 GBP2026-07publicdata.landregistry.gov.uk
    Green Belt share of the council area22 % of council area covered by green-belt polygons—planning.data.gov.uk
    Householder applications granted78.5 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Lawful development certificate applications (PS1)445 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 Hounslow
    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

    World Heritage, conservation areas and the borough's map

    Hounslow contains 1 World Heritage Site, 33 conservation areas and 519 listed building entries, including 32 at Grade I. The larger home extension route is closed on article 2(3) land, which covers both the World Heritage Site and conservation areas, and the council has also published 3 Article 4 directions.

    Designations follow historic features, not street names, so two houses a few streets apart can be in very different positions. We overlay the council's published boundaries on your plot, and a written result comes with the free constraints check.

    Housing mix and values

    54% of households live in a house and 45.7% own their home, so the eligible group is roughly half the borough. A terraced house averaged £611,320 on the latest Land Registry figures and a semi £716,213. For owners in that group the question is rarely whether to extend but how far, and the notification route is the one that tests the larger depth without a full application.

    22% of the borough is Green Belt. That does not enter the notification test, but it does shape the fallback: if a refusal takes you to a householder application on Green Belt land, the officer will weigh openness. We say so before any drawing starts.

    Drawing to the standard the council seems to demand

    The Order requires: Written description (depth beyond rear wall, max height, eaves height), site plan, addresses of adjoining premises, developer contact address. With Hounslow's record we treat that list as the floor. We add a section through the neighbour's nearest habitable window, a rear elevation showing the eaves against the boundary, and levels where the garden slopes.

    The site plan is prepared in the manner of 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) reads the set before submission, and the redraw after any council amendment request is included.

    The householder alternative

    Hounslow decided 689 householder applications in its latest year, granted 78.5% and decided 97.8% in time. A householder application lets the officer weigh the whole design, which can suit a scheme that is attractive but too deep for the notification test.

    For extensions inside ordinary limits a Lawful Development Certificate gives proof without any neighbour consultation; the council decided 445 of them. Our planning drawings service covers the full application.

    Survey detail that matters in west London

    Some Hounslow plots slope away from the road or toward the back. Ground levels change how tall an extension looks from next door, so we record spot levels at the rear wall, at the boundary and at the neighbour's door threshold, and draw the section through those points. A wall that is within the eaves limit on our side can look much taller to a neighbour on lower ground.

    We also record every outbuilding, shed and garage that affects the depth calculation. The Order measures from the original rear wall, and what already stands in the garden can matter too, because a deep extension plus a large outbuilding can feel overbearing together even when each is allowed alone.

    Our fixed fee and what it covers

    The fee we quote after the free check covers the measured survey, the design options if the neighbour test is close, the notification drawings, the second technologist's check and the submission. It also covers amendments the council asks for.

    We keep the arrangement simple because owners in a refusal-prone borough need to know what they are risking. The risk is the time a refusal costs, and the council fee, which is paid to the council and not to us.

    Nearby boroughs and where else we work

    Hillingdon to the north-west grants most of the notifications it decides, and Hammersmith and Fulham to the east decides very few, so Hounslow sits between two quite different habits. Our Hounslow area page lists every other service we offer in the borough.

    Whatever the route, the quote follows the facts of the address. We give you our reading of the odds in plain language and leave the decision with you.

    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 Hounslow

    Prior approval drawings nearby

    Questions

    How often does Hounslow refuse larger home extensions?

    In the latest published year it refused 59 and granted 20.

    Does the World Heritage Site affect my house?

    Only if your plot is inside it: World Heritage Site land is excluded from the route, as are the borough's 33 conservation areas, so we check boundaries first.

    How long does the council have?

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

    What does the council charge?

    £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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