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Lambeth, London

Flat conversion drawings in Lambeth

Lambeth protects family houses below a set floor area from being split, and larger ones can convert only if a family home with garden access is kept at ground level where it can be. We prepare flat conversion drawings in Lambeth from £1,195 including VAT, as MCIAT chartered architectural technologists, and we measure your house against that threshold before design begins.

From £1,195 (VAT included)

  • MCIAT chartered
  • £2m PI insured
  • LABC Partnered
  • Fixed fees, VAT included

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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 flat conversion drawings

    Seven 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.

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

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

    Lambeth's protection for family houses

    The Lambeth Local Plan 2021 protects smaller family homes in its housing policy. The floor-area line is 130 m2, measured on the house as originally built. Dwellings under that figure are protected from conversion to flats, and larger ones may convert if each unit meets the borough's housing standards.

    Two details decide a scheme. The first is the phrase "as originally built", which means a later extension may not lift a small house over the line, so we work from historic plans and the survey and not from the house as it stands today. The second is the ground floor: where practicable, the policy looks for a family home at ground level with access to the garden.

    That ground-floor family unit usually takes the largest share of the house, which pushes the second flat upstairs and can limit it to one or two bedrooms. We draw the stacking and the garden route first, then fit the upper flat around them. Our flat conversion drawings guide describes the rest of the set.

    Upper floors of a large yellow-brick Victorian house in London with chimney pots

    Local figures for Lambeth

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Family-suitable dwellings under 130m2 (as originally built) are protected from conversion to flats; larger ones may convert if units meet Policy H5 standards and, where practicable, a family home with garden access is provided at ground floor.130 m2—lambeth.gov.uk, Local Plan 2021, Policy H6, p.60, H6 A-B
    Minor application decisions748 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Minor applications granted79.9 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Minor applications decided in time92.5 % decided within 8 weeks or an agreed extended period1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications granted83.4 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Households living in a house24.8 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Conservation areas64 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries953 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Tree preservation orders339 tree preservation orders published by the council—planning.data.gov.uk
    Mayoral CIL charging band2 MCIL2 charging band (1-3)—london.gov.uk
    Mayoral CIL rate (indexed)72.73 £/m² (indexed, permissions granted in 2026)—london.gov.uk
    Borough CIL residential rate£602/m² (Zone A Waterloo and Vauxhall Nine Elms); £422/m² (Zone B Kennington, Oval and Clapham); £301/m² (Zone C Brixton, Herne Hill and Tulse Hill); £241/m² (Zone D Streatham, Streatham Hill and West Norwood)indexed rate 1 Jan to 31 Dec 2026 (residential incl. co-living)lambeth.gov.uk
    Change of use of a building to one or more separate dwellinghouses, not more than 10: per dwellinghouse, from 1 Apr 2026610 GBP per dwelling—ribblevalley.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 Lambeth
    Building regulations, layer by layerPart A: structure: Approved Document A: Structure, 2004 edition incorporating 2004, 2010 and 2013 amendments. Part B: fire safety: All dwellings: fire detection and alarm system minimum Grade D2 Category LD3 (BS 5839-6), mains-operated smoke alarms to BS EN 14604. Part L: insulation: New elements in existing dwellings, limiting U-values W/(m²·K): roof 0.15, wall 0.18, floor 0.18, windows 1.4 (or WER Band B), doors 1.4. Part K: stairs: 2.0 m clear headroom over stairs. Full plans application: Building control body must decide a full plans application within 5 weeks, or longer if agreed in writingPart A: structurePart B: fire safetyPart L: insulationPart K: stairsFull plans applicationABCDE

    Building regulations, layer by layer

    The Approved Documents that shape most house projects, from structure to the application itself.

    A · Part A: structure
    Approved Document A: Structure, 2004 edition incorporating 2004, 2010 and 2013 amendments
    B · Part B: fire safety
    All dwellings: fire detection and alarm system minimum Grade D2 Category LD3 (BS 5839-6), mains-operated smoke alarms to BS EN 14604
    C · Part L: insulation
    New elements in existing dwellings, limiting U-values W/(m²·K): roof 0.15, wall 0.18, floor 0.18, windows 1.4 (or WER Band B), doors 1.4
    D · Part K: stairs
    2.0 m clear headroom over stairs
    E · Full plans application
    Building control body must decide a full plans application within 5 weeks, or longer if agreed in writing

    Design guidance for alterations and basements

    Lambeth publishes its detailed design guidance in numbered parts. Part 4, the Lambeth Design Guide SPD Part 4: Building Alterations, Extensions and Retrofit, governs alterations, and Lambeth Design Guide SPD Part 2: Advice for All Development sets general standards for all schemes. Where a lower floor would become a home of its own, Lambeth Design Guide SPD Part 5: Basements adds basement rules.

    We read the relevant part against your address and show the result on the drawings, for example the depth of any rear alteration, the window pattern on the front and the position of bin and cycle stores. Each is a small decision, but together they decide whether an officer sees a considered conversion or a cramped one. A short pre-application check with the planning service can also be worthwhile on a borderline house, and we prepare the drawings that make that conversation precise.

    Sound and height are checked alongside. The London Plan asks for 2.5 m floor-to-ceiling across most of each flat, and Approved Document E sets sound targets between them.

    How Lambeth decides smaller applications

    A conversion into two or three flats is a minor application. In the latest twelve months the council decided 748, granted 79.9 per cent and decided 92.5 per cent inside eight weeks or an agreed extension.

    The council decided more minor applications than householder ones, with 595 householder decisions and 83.4 per cent of them granted. Only 24.8 per cent of households live in a house and 33 per cent own their home, so a freestanding or terraced house is a scarce asset and each application is read carefully.

    We put the area schedule, a statement of how the policy is met and the amenity layout into the first set, so the officer's first reading finds the evidence.

    Heritage, trees and the cost side

    Lambeth has 64 conservation areas, 953 listed building entries, 12 Article 4 directions and 339 tree preservation orders. With that many designated areas, it is worth checking early whether your street is one.

    On cost, the Mayor's levy is in band 2 with an indexed rate of £72.73 per square metre, and Lambeth's own levy is zoned by area, with rates in the table. The planning fee is £610 for each flat created. A terraced house averages about £796,865 and a flat about £439,289, and the twelve-month price change is -6.3 per cent.

    See the Lambeth area page for the borough's wider constraints.

    What we produce

    Existing and proposed floor plans, elevations, sections, a block plan and a schedule of areas by flat, with the original floor area calculated and shown. If you later sell the flats separately, each needs lease plans. For a neighbouring comparison see flat conversion drawings in Southwark.

    What you receive

    Building regulations section drawing showing the construction build-up
    Sample drawing. Building regulations section showing construction build-up for a building control check.
    Red-brick mansion blocks and shopfronts on a street corner
    Unit by unit
    Move up and down — the nearest units slide out.

    Other services in Lambeth

    Flat conversion drawings nearby

    Questions

    Can I convert a Lambeth house if it was extended after it was built?

    The council measures the house as originally built, so an extension does not help a house that began below the threshold.

    What must the ground floor contain?

    Where practicable the policy looks for a family home at ground floor with access to the garden, which affects how the flats are stacked.

    Which design guidance applies?

    The Lambeth Design Guide parts on alterations and on advice for all development, plus the basements part where a lower floor becomes a home.

    What if my house is just over the threshold?

    It may convert, but each flat must then meet the borough's housing standards and the ground-floor family home test. We draw the options and show where each one stands before you commit.

    How much is the planning fee?

    It is £610 for each flat created, paid to the council.

    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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