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Lewisham, London

L-shaped dormer drawings in Lewisham

L-shaped dormer drawings in Lewisham begin with a check that surprises many owners: the council has published 57 Article 4 directions, and each can remove a permitted development right on the streets it covers. Add 30 conservation areas and the route depends on your road.

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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 l-shaped dormer drawings

    Nine 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.

    8. Building regulations

      Technical drawings are coordinated with the structural engineer's calculations, the drainage and the planning conditions.

    9. Approval and hand-over

      Building control approval, then a next-steps pack covering the commencement notice, party wall timing and CIL.

    Free redraws until approval. Every drawing set is checked independently, and the checker is never the person who drew it.

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    Slate-clad roof extension on a yellow-brick London terraced house

    Article 4 directions in Lewisham and what they do to a roof

    An Article 4 direction does not ban work. It takes a named right away in a named area, so that the work needs an application instead. Lewisham's 57 directions cover 89 mapped areas, and they differ in which rights they remove. We read the wording of every direction that reaches your property rather than treat the map as a yes or no.

    The conservation areas are the second filter. The borough has 30, and inside any of them an L-shaped dormer is not permitted development. Historic England adds 367 list entries and the borough contains 1 World Heritage Site within its boundary, with 21 entries on the Heritage at Risk Register.

    Where no direction, conservation area or listing applies, the national volume rule decides: 40 m³ (terrace house) / 50 m³ (any other house) additional roof volume. We measure the roof on survey and tell you which side of that line the design falls.

    Converted loft bedroom with roof windows and a Juliet balcony

    Local figures for Lewisham

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Article 4 directions57 Article 4 directions published by the council—planning.data.gov.uk
    Article 4 direction areas89 Article 4 direction area polygons published by the council—planning.data.gov.uk
    Conservation areas30 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries367 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Heritage at Risk entries21 Heritage at Risk Register entries within the LPA boundary (Historic England)—planning.data.gov.uk
    Householder decisions578 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications granted89.4 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications decided in time95.2 % decided within 8 weeks or an agreed extended period1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Domestic gardens share of land (GLUD 2005)31.1 % of land that is domestic garden (GLUD 2005)2005data.london.gov.uk
    GPDO 2015 Sch 2 Pt 1 Class B, para B.1(d)40 m³ (terrace house) / 50 m³ (any other house) additional roof volume—legislation.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 Lewisham
    Loft enlargement in section: the permitted development limitsExtra roof volume allowed: 40 m³ (terrace house) / 50 m³ (any other house) additional roof volume. Set-back from the eaves: Original eaves maintained; enlargement set at least 0.2 m from the eaves measured up the roof slope, so far as practicable (not required for hip-to-gable or roofs joining a rear/side extension). Height limit: No part higher than the highest part of the existing roofABC

    Loft enlargement in section: the permitted development limits

    A dormer on the rear slope, with the limits that decide whether it needs planning permission.

    A · Extra roof volume allowed
    40 m³ (terrace house) / 50 m³ (any other house) additional roof volume
    B · Set-back from the eaves
    Original eaves maintained; enlargement set at least 0.2 m from the eaves measured up the roof slope, so far as practicable (not required for hip-to-gable or roofs joining a rear/side extension)
    C · Height limit
    No part higher than the highest part of the existing roof

    Policy documents for an L-shaped dormer in Lewisham

    The council's guidance for extensions is the Alterations and Extensions SPD, applied under the Lewisham Local Plan 2020-2040. That plan was adopted in 2,025, so its design policies are recent, while the extensions guide is older. Where the two differ in emphasis, we cite both and draw to the stricter reading.

    The council also publishes the Small Sites SPD, which concerns new homes on small plots rather than roofs, so we do not lean on it for a dormer. We read the extensions guide and the plan policies, and we expect officers to judge a roof against the character of the street.

    We therefore draw the L as part of a street scene. The elevation shows your roof and the roofs either side, so the officer can see the pattern the dormer joins or breaks. Where the neighbours have already built dormers, we photograph and draw them, because a precedent two doors away is the best evidence that your proposal fits. Where nobody has built one, we say so in the note and argue the case on proportion alone.

    Gardens, levy and what this means for cost

    Domestic gardens make up 31.1% of Lewisham's land in the national land-use database. That means a rear roof is seen from the gardens of several houses, and the council gives that view weight.

    The Mayor of London levy for permissions granted this year is 72.73 pounds per square metre of new floorspace, and the borough levy is read from the council schedule for the address. Neither normally applies to a conversion inside the existing roof, but we calculate the added area from the drawings and say so on the quote.

    A second cost is the party wall process. Terraces here share roof structure, so we show the party wall lines on the plan and prepare the information your surveyor needs. The third is structure: the junction between the two roofs of an L carries load from two directions, so the steel sizes from the engineer should be known before the builder prices the job.

    How Lewisham has been deciding householder cases

    The council decided 578 householder applications in the latest year and granted 89.4%. 95.2% were decided inside eight weeks or an agreed extension.

    A good grant rate sits alongside many designations, which tells us officers approve schemes that are proportionate and well drawn. We aim to show that early, with a clear section and a street-scene elevation, and our planning drawings in Lewisham page lists the full set of sheets.

    Where a dormer qualifies as permitted development despite the borough's designations, a lawful development certificate in Lewisham gives written proof that helps at sale.

    Other Lewisham roof options

    Not every Lewisham house needs the L. Dormer loft conversion drawings in Lewisham cover a simpler dormer, and loft conversion drawings in Lewisham set out the stair and fire rules. For the whole borough, see architectural drawings in Lewisham, or compare L-shaped dormer drawings in Greenwich.

    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.
    Brick cottage with a tiled roof, chimneys and a front dormer window
    Storey by storey
    Move up and down — the car travels between floors.

    Other services in Lewisham

    L-shaped dormer drawings nearby

    Questions

    Does an Article 4 direction stop an L-shaped dormer in Lewisham?

    It can. Lewisham has published 57 directions, each removing named rights in a defined area. We read the wording that applies to your address before telling you the route.

    What share of Lewisham householder applications are granted?

    89.4% of householder decisions in the latest year were granted. It is a borough figure and not a forecast for your roof.

    Does a conservation area in Lewisham allow an L-shaped dormer?

    Only by planning application. The borough has 30 conservation areas, and a roof enlargement there is not permitted development.

    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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