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Lewisham, London

Rear extension drawings for Lewisham houses

Lewisham's Alterations and Extensions SPD gives a rear extension three measurable checks: a depth of 3 m on a terrace or semi, a boundary height that depends on length, and a daylight line at 45 degrees to the neighbour's window. We fit your design inside all three and put the proof on one envelope sheet. Price: £695.

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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 rear extension 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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    Finished white-rendered rear house extension with large glazed doors

    Lewisham's depth, boundary height and daylight guide

    Under the SPD, a rear extension on a terraced or semi-detached house should generally be no more than 3 m deep. A detached house or a large plot can go further, but no extension should take more than half the depth of the original garden. On a short garden the half-depth limit is the one that arrives first.

    Height at the boundary is tied to length. The SPD gives 3 m long / 3 m high; 2.5 m on boundary if longer. A design at the basic depth can use the first height, while a longer one should lower the boundary wall or expect an objection from the neighbour and the officer.

    Daylight is the third check. The guide draws lines at 45 degrees upwards and sideways from the centre of the neighbour's affected window, and development higher and wider than both lines may cause unacceptable daylight loss. We draw both lines on the plan and the section.

    For an owner this reduces to a method. Take the lesser of the depth limit and half the garden, compare the boundary height with the length, and draw the daylight lines to the neighbour's window. The shape that fits inside all three is the likely envelope.

    Two-storey rear extension under construction on a semi-detached house

    Local figures for Lewisham

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Rear extensions should generally be no more than 3 m deep for terraced or semi-detached houses (deeper possible for detached or large plots) and never more than half the depth of the original garden.3 m—lewisham.gov.uk, Lewisham Alterations and Extensions SPD 2019, p.28, para 4.2.3
    Extensions up to 3 m long should be no more than 3 m high on the boundary; longer than 3 m and over 2.5 m high on the boundary is unlikely to be supported.3 m long / 3 m high; 2.5 m on boundary if longer—lewisham.gov.uk, Lewisham Alterations and Extensions SPD 2019, p.28, para 4.2.3
    45 degree daylight guide: lines at 45 degrees upwards and sideways from the centre of the neighbour's affected window; development higher and wider than both lines may cause unacceptable daylight loss.45 degrees—lewisham.gov.uk, Lewisham Alterations and Extensions SPD 2019, p.22, para 3.3.15
    Conservation areas30 named conservation areas published by the council—planning.data.gov.uk
    Article 4 directions57 Article 4 directions published by the council—planning.data.gov.uk
    Listed building entries367 list entries (Historic England, within the LPA boundary)—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
    Larger home extension prior approvals granted2 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Larger home extension prior approvals refused46 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    GPDO 2015 Sch 2 Pt 1 Class A, para A.1(f)(i)3 m (attached) / 4 m (detached) beyond the original rear wall, single storey—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
    Single-storey rear extension: the permitted development limitsDepth beyond the original rear wall: 3 m (attached) / 4 m (detached) beyond the original rear wall, single storey. Maximum height: 4 m. Within the zone near the boundary: Eaves no higher than 3 m where within 2 m of the curtilage boundary. Larger extension under prior approval: 6 m (attached) / 8 m (detached), single storey, height max 4 m; not on article 2(3) land or an SSSIABCD

    Single-storey rear extension: the permitted development limits

    The house in section with a rear extension; the dashed lines mark the zone near the boundary.

    A · Depth beyond the original rear wall
    3 m (attached) / 4 m (detached) beyond the original rear wall, single storey
    B · Maximum height
    4 m
    C · Within the zone near the boundary
    Eaves no higher than 3 m where within 2 m of the curtilage boundary
    D · Larger extension under prior approval
    6 m (attached) / 8 m (detached), single storey, height max 4 m; not on article 2(3) land or an SSSI

    One envelope sheet for three tests

    Our survey records the figures that feed each test: the length of the garden, the heights at the boundary and the position of the neighbour's window. We then build the envelope sheet, which shows the half-depth line, the boundary heights and the daylight lines in plan and section together.

    We also keep a short written note of the three figures for your plot. It travels with the drawings, so a builder, a neighbour or a case officer can see in one glance why the extension is the size it is and not a little deeper.

    The sheet lets us test options quickly with you, and it shows why one shape fits and another does not. Some plots are limited by garden length and others by the neighbour's window, and knowing which saves a design round.

    Domestic gardens cover 31.1 per cent of the borough's land in the Greater London Authority's land-use data, which is why the first test matters, and the drawings show the garden left after the build.

    Where a house has a rear return and a small yard, a common design is a single-storey extension beside the return with rooflights. We draw the junction with the existing wall in detail, because that is where an officer judges quality.

    Article 4 directions, conservation areas and prior approval

    Lewisham has 30 conservation areas and 57 Article 4 directions over 89 mapped areas, and these can remove permitted rights. We check the address before suggesting any route. Historic England lists 367 entries in the borough, and a listed house needs its own consent.

    Where rights remain, a deeper extension can use prior approval, but the return shows 2 larger home extension prior approvals granted against 46 refused. That ratio is why we usually advise a householder application for depth beyond the guide.

    The council fee for that application is £548, paid to the council.

    Householder decisions in Lewisham

    In its latest published year Lewisham decided 578 householder applications, granted 89.4 per cent and decided 95.2 per cent in time. They cover all householder work, so they help with the programme and say nothing about a particular house.

    We advise starting the building regulations drawings once the planning design is settled, so the structure, insulation and drainage are ready for the builder as soon as permission is given.

    What the set includes and what it costs

    A Lewisham set shows existing and proposed floor plans, elevations and sections, a location plan and block plan, with the daylight lines marked. Price, fixed before you commit: £695. A second chartered technologist checks every sheet, and we redraw at no charge if the council asks for changes.

    The first step is a visit to measure the house and garden, note the neighbour's windows and photograph the rear. You see the drawings before anything is submitted.

    For the borough view see architectural drawings in Lewisham, or the London guide to rear extension drawings. To go beyond the rear alone, look at wraparound extension drawings in Lewisham or side return extension drawings in Lewisham. Nearby, compare Greenwich, Bromley and Southwark.

    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.
    House extension under construction with scaffolding, new glazed doors and building materials
    Every side considered
    Flick across the turntable to spin it.

    Other services in Lewisham

    Rear extension drawings nearby

    Questions

    How deep can a rear extension be in Lewisham?

    Generally no more than 3 m on a terraced or semi-detached house, and never more than half the depth of the original garden.

    What is Lewisham's daylight guide for extensions?

    Lines at 45 degrees upwards and sideways from the centre of the neighbour's affected window. Development higher and wider than both may cause unacceptable daylight loss.

    Does Lewisham have Article 4 directions that affect extensions?

    Yes, 57 of them, which can remove permitted development rights. We check your address before drawing.

    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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