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Bright finished basement room with a glass-balustrade staircase, high windows and a built-in desk
Photograph: Point3D Commercial Imaging Ltd.

01Croydon, London

Basement and cellar conversion drawings in Croydon

Croydon has no basement policy in our records, and gardens cover 32.8% of its land in an older survey, so a cellar or basement conversion is judged on the case in front of the officer. We draw the existing cellar or the new lower floor, the structure and the escape route from £1,995 including VAT.

From £1,995 (VAT included)

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    02The brief

    Where Croydon's policy runs out

    The Croydon Local Plan 2018 is the document we search for basement limits, and none on depth, garden share or storeys has come to light. The London Plan fills the space with a direction to boroughs: Boroughs should set policies on large-scale basements where this is a local issue.

    In a conservation area the council's Conservation Areas General Guidance SPD applies too, and we read it before design starts.

    Rear view of brick terraced houses in London with slate roofs and chimney stacks along the shared roofline
    Brick house being extended, with a wide new opening supported over the ground floor
    Photograph: Brett Jordan

    03The record

    Local figures for Croydon

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Domestic gardens share of land (GLUD 2005)32.8 % of land that is domestic garden (GLUD 2005)2005data.london.gov.uk
    Conservation areas19 named conservation areas published by the councilNo periodplanning.data.gov.uk
    Listed building entries180 list entries (Historic England, within the LPA boundary)No periodplanning.data.gov.uk
    Grade I listed entries14 list entriesNo periodplanning.data.gov.uk
    Households living in a house60.2 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Green Belt share of the council area25 % of council area covered by green-belt polygonsNo periodplanning.data.gov.uk
    Householder applications granted86.6 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder decisions786 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Local planCroydon Local Plan 2018No periodcroydon.gov.uk
    Supplementary planning documentConservation Areas General Guidance SPDNo periodcroydon.gov.uk
    London Plan 2021 Policy D10(A)Boroughs should set policies on large-scale basements where this is a local issueNo periodlondon.gov.uk
    Party Wall etc. Act 1996 s6(1), s6(2), s6(5)Adjacent excavation notice at least 1 month before work: within 3 m and deeper than the neighbour's foundations, or within 6 m and cutting a 45° line from their foundationsNo periodlegislation.gov.uk
    Approved Document B Vol 1, para 2.16Basement storeys with habitable rooms need an escape window or external door, or a protected stair to a final exitNo periodgov.uk
    Householder: alterations/extensions to a single dwellinghouse, from 1 Apr 2026548 GBPNo periodribblevalley.gov.uk

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

    Croydon7 neighbouring councils
    Councils bordering Croydon

    04The streets

    Householder applications by street in Croydon

    Streets in Croydon with the most householder applications, and the share approved
    StreetApplicationsApproved
    Devonshire Way3556%
    Mount Park Avenue3079%
    Farley Road2885%
    Chaldon Way2592%
    Norbury Hill2482%
    Pollards Hill South2463%
    Bradmore Way2387%
    Woodcote Valley Road2376%
    Littleheath Road2264%
    Valley Road2264%
    Shirley Road2174%
    Upfield2065%
    Arkwright Road1983%
    Georgia Road1963%
    Caterham Drive1878%

    Counts of householder applications by street; no individual applications are shown. Streets with fewer than five applications are left out.

    GLA Planning London Datahub, householder applications

    05The drawing

    A basement in sectionA, Party wall notice for excavation: Adjacent excavation notice at least 1 month before work: within 3 m and deeper than the neighbour's foundations, or within 6 m and cutting a 45° line from their foundations. B, Escape from basement rooms: Basement storeys with habitable rooms need an escape window or external door, or a protected stair to a final exitAB

    A basement in section

    A house and garden over a single-storey basement. The lettered marks show the limits the legend gives.

    A Party wall notice for excavation
    Adjacent excavation notice at least 1 month before work: within 3 m and deeper than the neighbour's foundations, or within 6 m and cutting a 45° line from their foundations
    B Escape from basement rooms
    Basement storeys with habitable rooms need an escape window or external door, or a protected stair to a final exit
    The basement in three dimensions3D
    Scroll the page: the model turns with it.

    06The detail

    A cellar that is already there

    Some Croydon houses already have a cellar, and turning one into a habitable room is a different job from excavating a new floor. The first is mostly about headroom, damp and the stair. The second brings in structure, drainage and the neighbours.

    Where the house is among the 180 list entries, with 14 at Grade I in the borough, the conversion can touch historic fabric, and listed building consent drawings in Croydon covers the consent side. A roof change on the same house is a separate question for mansard roof drawings in Croydon.

    Large plots and the green belt

    Houses and bungalows are home to 60.2% of Croydon households, and 25% of the council's area is mapped as green belt. On a long rear plot, or one that touches the green belt, we check the designation before drawing anything that shows above the lawn.

    The council publishes 19 conservation areas, which we check at the same time.

    The wall next door and the stairs up

    Excavation near a neighbour's foundations falls under the Party Wall etc. Act 1996: Adjacent excavation notice at least 1 month before work: within 3 m and deeper than the neighbour's foundations, or within 6 m and cutting a 45° line from their foundations.

    Habitable rooms below ground need an exit: Basement storeys with habitable rooms need an escape window or external door, or a protected stair to a final exit. Alongside our fee, the council charges its own householder fee of £548. Other councils write firm limits, as the basement conversion hub shows with Westminster.

    Planning sheet for a single-storey rear extension: proposed ground floor plan and rear elevation, with the Property Architecture title block
    Sample drawing. Proposed plan and rear elevation from a planning application set, sheet 03 at 1:50.

    07The papers

    What the drawings rest on

    Georgian brick terrace with sash windows, arched fanlight doorways, stone steps and iron railings in LondonListed building consent
    Photograph: Lorenc Memaga
    Structural calculation sheet for a steel beam over a new rear opening, with the load diagram, loading table and section checks
    Sample drawing. Beam B1 over a new rear opening: loading, bending moment and section checks.

    08Correspondence

    Questions

    Is there a depth limit for a basement in Croydon?

    None has come to light in the Local Plan we search. Because the position can change, we check the council's current stance when we survey and tell you before the design is fixed.

    Can I convert an existing cellar in Croydon without planning permission?

    It depends on the works and the house. Fitting out a cellar that is already there is a different question from digging a new one, and listed status or a conservation area changes the answer. A free constraints check settles it before we quote.

    Does the green belt affect a Croydon basement?

    It can, for anything visible above ground such as a lightwell or a new opening. The council's area is 25% green belt on the map, and we check your plot against it at the start.

    How often does Croydon grant householder permission?

    The council granted 86.6% of its 786 householder decisions in the latest year of its statistics.

    Rows of brick terraced houses and gardens on a residential street

    86.6%

    Householder applications granted, Croydon, 1 July 2025 - 30 June 2026. Source: assets.publishing.service.gov.uk

    Photograph: Altaf Shah

    09Further reading

    Other services in Croydon

    Basement conversion drawings nearby

    10Sources

    Sources and dates

    Licences

    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.

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    Basement conversion drawings in Croydon