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Large white roughcast house with dormer windows and tall chimneys on Belvedere Drive in Wimbledon, a blue convertible in front
Photograph: David Anstiss (CC BY-SA 2.0)

01Planning

How much does prior approval for a larger extension cost in London?

Prior approval for a larger single-storey rear extension in London costs two things: our drawings, from £715 inc survey, or £200 less if you supply measured drawings, with no VAT to add, and the council's notification fee of £249. It avoids the £548 full application fee.

From £715 inc survey (£515 if you supply measured drawings)

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    Write to us before 3pm and we reply the same working day. Redraws are free until approval.

    What each route costs

    A larger home extension goes through a notification to the council, not a full application. The council charges £249 for that notification from 1 April 2026. The full householder application it replaces costs £548. Our fee for the drawings is from £715 inc survey, whichever route you take.

    So the council's saving is £299, and the real value is in what the route allows: depth well beyond the ordinary permitted limits, in exchange for a check on the neighbours.

    Two ways to a deep rear extensionOur drawings: £715 inc survey; Council fee, larger-home notification: £249; Council fee, full householder application: £548; VAT on our fee: none to add£Our drawings£715 inc survey£Council fee, larger-home notification£249£Council fee, full householder application£548£VAT on our feenone to add
    Council fees as in the national table from 1 April 2026.

    How deep this route allows

    Ordinarily a rear extension may go 3 metres on an attached house and 4 on a detached one. With prior approval a single-storey extension may reach 6 metres attached or 8 detached, no higher than 4 metres. It is not available on article 2(3) land such as conservation areas, nor where a site of special scientific interest is involved.

    Flats are excluded: householder permitted development does not apply to flats or buildings containing flats. We make a written check that your house qualifies before you pay for anything else.

    A terrace of yellow-brick Victorian cottages with white sash windows and red door surrounds on a London street
    A terrace of Victorian cottages: the depth of a rear extension is always measured from the original rear wall.Photograph: trailerfullofpix, CC BY-SA 2.0

    What happens after we send it

    The council tells the adjoining owners and gives them at least 21 days to send in representations. If a neighbour objects, the council considers the effect on their amenity before deciding whether prior approval is needed.

    If the council has not told you its decision within 42 days, development may begin. We submit the notification and answer the officer's replies at no extra fee from us.

    When to choose the full application instead

    If your house cannot use the route, or you want a shape the limits do not allow, the answer is a full application. Our planning drawings cover that, and the council charges £548.

    We decide the route with you after the free check. Learn more on our prior approval drawings page, and see the ordinary limits in our rear extension guide.

    A bright white kitchen with a rooflight above and glazed doors to the garden
    A deep kitchen extension with glazed doors: at 6 metres, the room is only as good as the daylight reaching the back.Photograph: eosrooflights, CC BY 2.0

    Next step

    Send the address and how far back you want to build. We check it qualifies and tell you the route and the fee.

    From idea to notificationFree check: does it qualify?; Fixed fee in writing; Survey and drawings; Notification sent to the council; Neighbours consulted, then a decisioni

    Free check: does it qualify?

    ii

    Fixed fee in writing

    iii

    Survey and drawings

    iv

    Notification sent to the council

    v

    Neighbours consulted, then a decision

    A free redraw follows if the officer asks for less depth.

    The figures, with sources

    1. 6 m / 8 m

      Furthest a single-storey rear extension may reach under the larger-home route, attached and detached.

      Source: General Permitted Development Order 2015, Schedule 2, Part 1, Class A, checked 15 Oct 2026

    2. 4 m

      Tallest a single-storey rear extension may be under the prior approval route.

      Source: General Permitted Development Order 2015, Schedule 2, Part 1, Class A, checked 15 Oct 2026

    3. 21 days

      Shortest period the council gives adjoining owners to send in representations.

      Source: General Permitted Development Order 2015, Schedule 2, Part 1, Class A.4, checked 15 Oct 2026

    4. 42 days

      Time after which work may start if the council has not notified a decision.

      Source: General Permitted Development Order 2015, Schedule 2, Part 1, Class A.4, checked 15 Oct 2026

    5. £249

      Council charge for a larger-home extension notification from 1 April 2026.

      Source: Ribble Valley Borough Council, national fee table from 1 April 2026, checked 17 Oct 2026

    6. £548

      Council charge for the full householder application if the notification route is closed.

      Source: Ribble Valley Borough Council, national fee table from 1 April 2026, checked 17 Oct 2026

    7. Art. 2(1)

      Householder permitted development cannot be used on a flat or on a building that contains flats.

      Source: General Permitted Development Order 2015, article 2, checked 15 Oct 2026

    Questions

    Can neighbours stop a larger extension?

    They can object, and the council then considers the effect on their amenity. The council decides; the neighbours do not have a veto.

    Do I still need building regulations?

    Yes. Prior approval is a planning route; building regulations apply separately.

    What if the council says prior approval is needed and refuses it?

    We can redraw a shallower scheme or take you to a full application; the cost is quoted first.

    Is it worth it for 4 metres or less?

    Often not: within the ordinary limits you may need no notification at all. We tell you in the free check.

    The fee for prior approval (larger home extension)

    Prior approval (larger home extension)

    from £715

    inc survey (£515 if you supply measured drawings). No VAT to add.

    Get a fixed quote from £715

    What you get

    • A survey of the house and the neighbours' rear windows
    • A written check that the house qualifies
    • Plans and elevations set against each limit
    • The notification submitted for you
    • A free redraw if the officer asks for less depth
    Georgian brick terrace with sash windows, arched fanlight doorways, stone steps and iron railings in London

    6 m / 8 m

    Furthest a single-storey rear extension may reach under the larger-home route, attached and detached. Source: legislation.gov.uk

    Photograph: Lorenc Memaga

    02Guides

    More guides

    Kensington street lined with brick townhouses and lit streetlamps beneath an orange dusk sky

    Send us the address of your house.

    We look up the conservation area, listing and Article 4 position, then reply with a fixed fee. A message before 3pm is answered the same working day.

    Ask for a fixed feeCall 020 7131 9703WhatsApp
    Prior Approval Extension Cost in London: From £715