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Slate-clad roof extension on a yellow-brick London terraced house
Photograph: Daniel Sikpi

01Greenwich, London

Mansard roof drawings for Greenwich houses

Greenwich's mansard test, in the council's words, is “established character required”. Where a street has no mansard tradition, the council refuses one, so the first drawing we make is of your roofline and the roofs either side, from £845 including VAT.

From £845 (VAT included)

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    02The brief

    The established-character test

    The council refuses mansard extensions where the area has no mansard character already, and its shorthand is “established character required”. Where one is acceptable it is typically a flat-topped or double-pitched roof behind a front parapet. The exact slope limits sit in the table.

    A terrace of unbroken pitched roofs is therefore a harder case than a street where roofs have been altered over time. The survey records which of the two yours is.

    Upper floors of a large yellow-brick Victorian house in London with chimney pots
    Converted loft bedroom with roof windows and a Juliet balcony
    Photograph: Imad Clicks

    03The record

    Local figures for Greenwich

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Mansards (flat-topped or double-pitched) acceptable only where established in typology/streetscape, typically behind a front parapet<70 deg lower / <30 deg upper slope degreesNo periodroyalgreenwich.gov.uk, Royal Greenwich Urban Design Guide SPD (adopted October 2023), Chapter I, para i.72, p.278
    Mansard extensions refused where not already an established character in the areaestablished character requiredNo periodroyalgreenwich.gov.uk, Royal Greenwich Urban Design Guide SPD (adopted October 2023), Chapter I, para i.73, p.278
    Mansards set back from front and rear facades; raised party-wall chimney stacks reinstated at higher levelset back from front and rear facadesNo periodroyalgreenwich.gov.uk, Royal Greenwich Urban Design Guide SPD (adopted October 2023), Chapter I, para i.74, p.278
    Dormer guideline: below ridge, in from each party wall, above eaves0.5 m from ridge, party walls and eaves mNo periodroyalgreenwich.gov.uk, Royal Greenwich Urban Design Guide SPD (adopted October 2023), Chapter I, para i.66 and Fig i.30, pp.274-275
    Loft conversions accepted only if headroom achieved without raising ridge; ridge must stay continuous along terraceno ridge raiseNo periodroyalgreenwich.gov.uk, Royal Greenwich Urban Design Guide SPD (adopted October 2023), Principle I.3.1, pp.274 and 278
    Full-width box dormers discouraged; hip-to-gable conversions not supportedno full-width box dormer; no hip-to-gableNo periodroyalgreenwich.gov.uk, Royal Greenwich Urban Design Guide SPD (adopted October 2023), para i.68, Figs i.34 and i.36, pp.274 and 277
    Class B, condition B.2(b)(i)(aa)Class B requires the original eaves to be maintained or reinstated, which a parapet-fronted mansard normally removesNo periodlegislation.gov.uk
    Class AA, para AA.1(b)Class AA is not available on article 2(3) landNo periodlegislation.gov.uk
    Householder: alterations/extensions to a single dwellinghouse, from 1 Apr 2026548 GBPNo periodribblevalley.gov.uk
    Conservation areas23 named conservation areas published by the councilNo periodplanning.data.gov.uk
    Listed building entries540 list entries (Historic England, within the LPA boundary)No periodplanning.data.gov.uk
    Householder applications granted77.1 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk

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

    Greenwich5 neighbouring councils
    Councils bordering Greenwich

    04The drawing

    A mansard roof in sectionA, Greenwich: lower slope: <70 deg lower / <30 deg upper slope degrees. B, Greenwich: set-back and parapet: set back from front and rear facades. C, Permitted development and the eaves: Class B requires the original eaves to be maintained or reinstated, which a parapet-fronted mansard normally removes. D, Additional storeys under permitted development: Class AA additional storeys exclude houses built before 1 Jul 1948 or after 28 Oct 2018. E, Fire protection to the stair: New storey above 4.5 m by loft conversion: protect the full escape route with fire-resisting doors (min E 20) and partitions (min REI 30)ABCDE

    A mansard roof in section

    A London terrace with a mansard behind the parapet. The lettered marks show the limits the legend gives.

    A Greenwich: lower slope
    <70 deg lower / <30 deg upper slope degrees
    B Greenwich: set-back and parapet
    set back from front and rear facades
    C Permitted development and the eaves
    Class B requires the original eaves to be maintained or reinstated, which a parapet-fronted mansard normally removes
    D Additional storeys under permitted development
    Class AA additional storeys exclude houses built before 1 Jul 1948 or after 28 Oct 2018
    E Fire protection to the stair
    New storey above 4.5 m by loft conversion: protect the full escape route with fire-resisting doors (min E 20) and partitions (min REI 30)
    The mansard in three dimensions3D
    Scroll the page: the model turns with it.

    05The detail

    How a mansard has to sit

    The guidance asks for a mansard to be set back from front and rear facades, and for raised party-wall chimney stacks to be reinstated at the higher level. On a loft conversion without a mansard the shorthand is “no ridge raise”: headroom must come without raising the ridge, which has to stay continuous along the terrace.

    Dormers are held to their own guideline, shown in the table, and the council's position on bulk is “no full-width box dormer; no hip-to-gable”. Those limits shape the design before any detail does.

    Conservation areas and listed roofs

    Greenwich has 23 conservation areas and 540 list entries, and Class AA is not available on article 2(3) land. A listed roof needs consent too, covered in listed building consent drawings in Greenwich.

    Class B requires the original eaves to be maintained or reinstated, which a parapet-fronted mansard normally removes. That is why a mansard normally goes through a full householder application.

    The drawing set and the fee

    The set records the terrace as built and as altered, so the officer can follow the ridge, the parapet and the chimney stacks across the party walls. The Party Wall etc. Act 1996 sets the notice: Party structure notice at least 2 months before work.

    Greenwich decided 624 householder applications in its published figures and granted 77.1%. The council fee is £548, separate from ours. A lower floor is a different application: basement conversion drawings in Greenwich.

    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.

    06The papers

    What the drawings rest on

    Brick cottage with a tiled roof, chimneys and a front dormer windowLawful development certificates
    Photograph: Tanya Barrow
    Loft floor plan marked up in an independent review, with three critical issues clouded and explained
    Sample drawing. A loft plan with the reviewer’s mark-up: stair pitch, dormer cheeks and roof ventilation.

    07Correspondence

    Questions

    Will Greenwich allow a mansard on my street?

    Only if mansards already form part of the area's character, because the council refuses them elsewhere. We survey the roofs along your street and tell you in the free constraints check whether a mansard exists there already, before you pay for drawings.

    Can I raise the ridge to get headroom in Greenwich?

    The council's shorthand is “no ridge raise”. Headroom has to be found without a higher ridge, and the ridge must stay continuous along the terrace.

    Are hip-to-gable and full-width box dormers possible?

    The guidance says “no full-width box dormer; no hip-to-gable”, so neither is a sound first choice. We draw the option the council can support.

    Rear view of brick terraced houses in London with slate roofs and chimney stacks along the shared roofline

    77.1%

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

    Photograph: Ben Hadfield

    08Further reading

    Other services in Greenwich

    Mansard roof drawings nearby

    09Sources

    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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    Mansard roof drawings in Greenwich