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Bexley, London

L-shaped dormer drawings in Bexley

Bexley grants the great majority of its householder applications, and three in four of its households live in a house or bungalow. We draw them for a fixed quote after a free constraints check, VAT included, using 94.6 per cent as a reason to be careful rather than casual.

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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.

    Request a fixed quote
    Converted loft bedroom with roof windows and a Juliet balcony

    The Bexley guide and how it reads an L-shaped dormer

    Bexley's householder document is the Design Guide SPD Part 2: Building Alterations and Extensions, read alongside the Design Guide SPD Part 1: Design Principles. It covers roof extensions in general terms and does not give an L-shaped dormer figure that we can cite, so the national limits set our outer edge and the guide's design tests set the detail.

    In plain terms the officer asks whether the roof looks like part of the house or a box added to it, and whether it overlooks the neighbours' gardens. We answer both on the drawings, with a rear elevation that shows the cladding and window proportions and a plan that shows the distance to the boundary.

    The wider policy is the Bexley Local Plan.

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

    Local figures for Bexley

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Conservation areas23 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries114 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Householder decisions877 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications granted94.6 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications decided in time99.4 % decided within 8 weeks or an agreed extended period1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Households living in a house75.3 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Owner-occupied households68.6 % of households owner-occupied (owned outright or with mortgage/loan)Census 2021nomisweb.co.uk
    Lawful development certificate applications (PS1)323 certificates2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.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.

    Councils bordering Bexley

    Householder applications by street in Bexley

    Streets in Bexley with the most householder applications, and the share approved
    StreetApplicationsApproved
    Rydal Drive3688%
    Danson Road3578%
    Glenhurst Avenue3491%
    Westwood Lane3494%
    Wren Road3389%
    Harland Avenue3297%
    Halfway Street3167%
    Northumberland Avenue3197%
    Okehampton Crescent3090%
    Upton Road2679%
    Bellegrove Road2591%
    Latham Road25100%
    Mayplace Road East2584%
    Walton Road25100%
    Wansunt Road2596%
    Counts of householder applications by street; no individual applications are shown. Streets with fewer than five applications are left out.Source: GLA Planning London Datahub, householder applications, all years held. Contains public sector information licensed under the Open Government Licence v3.0. Contains OS data © Crown copyright and database right 2026.
    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

    A high grant rate is not a free pass

    The council decided 877 householder applications in its latest year and granted 94.6 per cent, with 99.4 per cent decided in time. Those are strong figures for the borough as a whole.

    They cover every kind of householder scheme, though, from porches upwards. An L-shaped dormer is among the largest roof additions a house can take, so a scheme that ignores the set-backs can sit in the small refused share. We use the borough's own record as a reminder to show the officer a restrained design.

    The housing stock suits the L

    About 75.3 per cent of households in Bexley live in a house or bungalow, and 68.6 per cent own their home. Those are high shares, and they explain why roof extensions are such a common project here.

    Where a house was built with a two-storey back addition, that is the structure an L-shaped dormer continues over. The rule that allows the junction is: Eaves-retention and 0.2 m set-back do not apply where the enlargement joins the original roof to the roof of a rear or side extension.

    Limits on volume, height and protected areas

    Permitted development allows: 40 m³ (terrace house) / 50 m³ (any other house) additional roof volume. Height is limited by this: No part higher than the highest part of the existing roof. If the house is in a conservation area the position is: Class B roof enlargements are not permitted development on article 2(3) land.

    Bexley has 23 conservation areas and 114 Historic England list entries, and about 17 per cent of the borough is Green Belt. We check each against your address. If the house is clear, a Lawful Development Certificate in Bexley can prove the permitted route before the build starts. Over its last four reported quarters, to the end of March, the borough dealt with 323 lawful development certificate cases, so the route is well used.

    Building regulations details

    Whatever the route, the loft must meet the regulations. Party structure: Party structure notice at least 2 months before work. Stair headroom: Loft conversions where 2.0 m cannot be achieved: 1.9 m at the centre of the stair, 1.8 m at the side (half width). Fire protection: 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).

    These conditions are drawn on the plans and sections in our building regulations drawings in Bexley, so the builder and the inspector are working from the same page.

    A roof addition of this size normally needs new beams to carry the floor and the dormer cheeks, so the structural calculations travel with the drawings when they go to building control.

    Cost, checking and what to do next

    You receive existing and proposed plans, the roof section, elevations and location and block plans, for a fixed quote after a free constraints check, VAT included. Before release, each sheet goes to a chartered technologist who did not draw it. Amendments the council requests are redrawn at our cost until the application is approved.

    If the house has no back addition, dormer loft conversion drawings in Bexley are the better fit. The borough overview is architectural drawings in Bexley, and neighbours may find Bromley or Greenwich helpful.

    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
    Storey by storey
    Move up and down — the car travels between floors.

    Other services in Bexley

    L-shaped dormer drawings nearby

    Questions

    Does Bexley set a size limit for an L-shaped dormer?

    The council guide does not give a figure we can cite, so we work to the national limits and the guide's design tests.

    How likely is a Bexley householder approval?

    The council granted 94.6 per cent of 877 householder decisions in its latest year. That reflects modest schemes, and no application is certain.

    Can I prove the L is permitted development?

    Yes, with a certificate, provided the address is clear of designations. The borough dealt with 323 certificate cases over its last four reported quarters.

    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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