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Wandsworth, London

Flat conversion drawings in Wandsworth

Wandsworth draws its line at 130 sqm: a home at or below that size, as originally built, may only become flats if it is shown to be unsuitable for families. Our flat conversion drawings in Wandsworth start from £1,195 including VAT, prepared by MCIAT chartered architectural technologists, and they set out the evidence the policy asks for.

From £1,195 (VAT included)

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

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We use it to check conservation areas and constraints.
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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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    Red-brick mansion blocks and shopfronts on a street corner

    Two Wandsworth tests, depending on the size of the house

    The Wandsworth Local Plan 2023-2038 deals with conversions in a two-part policy. Below the size line, the burden is on you: the application must show the house is unsuitable for a family, which in practice means a layout, access or amenity reason that an officer can verify from the drawings. We prepare that argument as a short design note with annotated plans.

    Above the line, the policy asks for design rather than justification. The conversion needs at least one family-sized unit with direct access to a dedicated rear garden, with a policy minimum of 15 sqm garden, and no more than one studio or one-person unit. A large Victorian house in Balham or Putney can usually be arranged to meet both requirements, with a family maisonette on the ground and lower floors and a smaller flat above.

    The council's Housing SPD (covers rear extensions, basements, roof extensions and loft conversions) covers the external side of a conversion, such as rear windows and roof alterations, so the elevation drawings follow that guidance.

    Pencil resting on a dimensioned technical drawing beside a scale rule

    Local figures for Wandsworth

    Figures with their unit, period and source
    MeasureValuePeriodSource
    A dwelling of 130sqm or less (as originally built) may only be converted to flats if it is shown to be unsuitable for families.130 sqm—wandsworth.gov.uk, Local Plan 2023, Policy LP26, p.352, LP26 A
    Converting a dwelling over 130sqm needs at least one family-sized unit with direct access to a dedicated rear garden of at least 15sqm, and no more than one studio or 1-person unit.15 sqm garden—wandsworth.gov.uk, Local Plan 2023, Policy LP26, p.352, LP26 B
    Minor application decisions902 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Minor applications granted86.7 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Minor applications decided in time88.1 % decided within 8 weeks or an agreed extended period1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Conservation areas46 named conservation areas published by the council—planning.data.gov.uk
    Households living in a house31.4 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Average price, flat526,813 GBP2026-07publicdata.landregistry.gov.uk
    Mayoral CIL charging band1 MCIL2 charging band (1-3)—london.gov.uk
    Borough CIL residential rate£1,031.39/m² (Nine Elms Residential Area A); £475.34/m² (Nine Elms Residential Area B); £0 (Roehampton Charging Area); £448.43/m² (all other areas)rate for 2026 (schedule rates £575 / £265 / £0 / £250)wandsworth.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 Wandsworth
    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

    Heritage and Green Belt in Wandsworth

    The council publishes 46 conservation areas, and Historic England lists 312 buildings in the borough, with 8 entries on the Heritage at Risk Register. There is no Green Belt, at 0 per cent of the area.

    Conservation areas matter more than the listing count suggests, because they cover whole streets of the Victorian terraces that make the best conversions. Changes seen from the street, such as a second front door or bin store, are judged against the area's character, so we draw them in the elevations before the application goes in.

    How Wandsworth decides small housing schemes

    Wandsworth decided 2,123 applications of all types in the latest year, including 902 minor applications, of which 86.7 per cent were granted and 88.1 per cent decided in time. On the householder side, 977 decisions produced a 91.9 per cent grant rate.

    The grant rate includes schemes that already met policy when they were submitted. We use it as a reminder that evidence beats persuasion: area schedules, the garden dimension and the family unit labelled on the plans.

    Housing and values around the borough

    31.4 per cent of Wandsworth households live in a house or bungalow, and 42.5 per cent own their home. The average home sold for about £686,076, against £526,813 for a flat.

    That gap is the incentive and the trap. A flat sells well, but the policy forces you to keep a large family unit, and the family unit has to carry the cost. We often draw two layouts side by side so you can compare the area of each flat before choosing.

    Check your road's history before committing. The council's register at https://planning.wandsworth.gov.uk/wandsworth lists earlier conversions and refusals, and we search it as part of the free constraints check, so the drawings answer the arguments officers have already made nearby. A second chartered technologist then checks every sheet before issue.

    Levies and costs for new Wandsworth flats

    Wandsworth is in Mayoral levy band 1, at an indexed £96.97 per square metre for permissions granted this year. The borough's own levy varies by area: £1,031.39/m² (Nine Elms Residential Area A); £475.34/m² (Nine Elms Residential Area B); £0 (Roehampton Charging Area); £448.43/m² (all other areas). Check which area your address sits in before you buy.

    The council fee is £610 for each flat, and sound insulation between flats must meet Approved Document E: Separating walls 43 dB DnT,w+Ctr (min); floors and stairs 43 dB airborne (min), 64 dB L'nT,w impact (max) for dwellings formed by material change of use. We detail it in the building regulations drawings in Wandsworth.

    The application is built on our planning drawings in Wandsworth. The same service covers Lambeth, Merton and Richmond upon Thames, and the borough overview is at architectural drawings in Wandsworth.

    Our usual order is a free constraints check, a fixed quote, the measured survey, then two layouts in plan and 3D so you can compare the family unit with the smaller flat. If officers ask for changes we redraw at no charge until approval, without promising the decision.

    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.
    Rear view of brick terraced houses in London with slate roofs and chimney stacks along the shared roofline
    Unit by unit
    Move up and down — the nearest units slide out.

    Other services in Wandsworth

    Flat conversion drawings nearby

    Questions

    What is the size threshold for converting a house into flats in Wandsworth?

    Under the Local Plan, a home of 130 sqm or less, as originally built, may only be converted if it is shown to be unsuitable for families.

    What does a larger Wandsworth house need to include?

    At least one family-sized unit with direct access to a rear garden (policy minimum 15 sqm garden), and no more than one studio or one-person unit.

    How many minor applications does Wandsworth grant?

    86.7 per cent of 902 decisions in the latest published year.

    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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