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Merton, London

Dormer loft conversion drawings in Merton

Merton grants most householder applications, 92.9 per cent in its latest year, but decides only 85.2 per cent of them in time. A Merton dormer therefore needs a complete first submission. Our dormer loft conversion drawings for Merton houses start at £695 including VAT, drawn so the case officer has nothing to chase.

From £695 (VAT included)

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  • 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 dormer loft conversion 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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    Converted loft bedroom with roof windows and a Juliet balcony

    What decides a dormer loft conversion in Merton

    Our council data holds no numeric dormer clearance for Merton, so we do not quote one. The decision rests on the Merton Local Plan 2024 design policies and the Borough Character Study SPD, which describes the character of the borough's streets, and an officer applies them to your roof case by case.

    That puts weight on the drawing, because without a published margin the elevation has to persuade. We draw the dormer against the roofs either side, show it set well down from the ridge and clear of the eaves, and annotate the material so the finish is settled before it becomes a condition. The permitted development tests still frame the design: No enlargement beyond the plane of a roof slope that forms the principal elevation and fronts a highway, and the additional volume limit is 40 m³ (terrace house) / 50 m³ (any other house) additional roof volume.

    Where a client wants more than the permitted limits allow, the same drawings support a planning application, and we advise which route fits before the set is finalised.

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

    Local figures for Merton

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Conservation areas28 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries243 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Grade II* listed entries11 list entries—planning.data.gov.uk
    Heritage at Risk entries23 Heritage at Risk Register entries within the LPA boundary (Historic England)—planning.data.gov.uk
    Households living in a house60.4 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Average price, terraced686,591 GBP2026-07publicdata.landregistry.gov.uk
    Householder decisions759 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications granted92.9 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications decided in time85.2 % decided within 8 weeks or an agreed extended period1 July 2025 - 30 June 2026assets.publishing.service.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
    Class B, para B.1(f)Class B roof enlargements are not permitted development on article 2(3) land—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 Merton

    Householder applications by street in Merton

    Streets in Merton with the most householder applications, and the share approved
    StreetApplicationsApproved
    South Park Road2696%
    Lower Morden Lane2584%
    Coombe Lane2383%
    Pepys Road2377%
    Palmerston Road21100%
    Dorset Road2072%
    Marryat Road2094%
    Mostyn Road2089%
    Springfield Avenue1995%
    Vineyard Hill Road19100%
    Claremont Avenue1888%
    Queen's Road18100%
    Faraday Road1782%
    Gladstone Road1760%
    Stroud Road1794%
    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

    The houses behind Merton roofs

    60.4 per cent of Merton households live in a house and 55.6 per cent own their home. Prices vary sharply, from an average terraced house at £686,591 to a detached house at £2,338,085, and that spread changes what a dormer is worth and what owners expect from it.

    Large detached and semi-detached houses can carry deep, complicated roofs where a single dormer may be too small for the plan. On a terrace or a modest semi the dormer is usually a simpler job of one rear box. We tailor the brief to the roof, not the postcode.

    Gardens occupy 27.2 per cent of the borough's land, and the outlook from a new dormer window across those gardens is a likely source of a neighbour's letter.

    Conservation areas and listed roofs in Merton

    The borough has 28 conservation areas and 243 listed entries, with 11 at Grade II*. Class B roof enlargements are not permitted development on article 2(3) land. A house inside one of them takes the planning route by default.

    Merton's 23 Heritage at Risk entries are a reminder that old buildings here are sometimes fragile. If a listed or locally important house is yours, we begin with its heritage constraints and draw the dormer after that.

    For a house inside one of those areas we read the conservation area appraisal alongside the character study, because the appraisal names the roofs, chimneys and views the council wants kept, and the dormer is drawn around them.

    Merton's householder record and the clock

    The council decided 759 householder applications in its latest published year. Only 85.2 per cent were decided in time, against 92.9 per cent granted, so timing, more than refusal, is the risk to plan for.

    We plan around that: a complete submission with the section, elevations and block plan, and a site photograph set, reduces the risk of a validation delay. Merton also saw 22 larger-extension prior approvals granted and 80 refused, which is a signal that officers examine neighbour impact carefully.

    What the Merton dormer set includes

    You receive existing and proposed floor plans, the roof section, all elevations and the location and block plans. The new stair is checked against 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).

    The price is £695 including VAT, fixed before you commit, and a second MCIAT chartered technologist checks each sheet. If the council asks for changes we amend the drawings without a further fee.

    Dormers next to Merton

    Sutton and Wandsworth have their own roof guides: compare dormer loft conversion drawings in Sutton and Wandsworth. For a gentler roof scheme, see loft conversion drawings in Merton, or start from architectural drawings in Merton. The national rules are on the dormer loft conversion drawings hub.

    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 Merton

    Dormer loft conversion drawings nearby

    Questions

    Does Merton publish dormer measurements?

    Not in the sources we hold, so we draw to the Local Plan and the Borough Character Study and show the dormer set well in from the ridge and eaves.

    How long does Merton take to decide a householder application?

    In its latest year Merton decided 85.2 per cent in time. A complete first submission helps.

    Do I need planning permission for a dormer in Merton?

    Not always. Outside the 28 conservation areas and any direction, a dormer can be permitted development within the volume limits.

    What do dormer drawings cost in Merton?

    From £695 including VAT, fixed in advance. The council's fee is separate.

    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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