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City of London, London

Side return extension drawings in the City of London

The Square Mile has almost no side returns to extend. Only 2 per cent of City households live in a house, and the council decided just 1 householder application in its latest year. If you own one of the few houses, our side return extension drawings for the City of London start at £745 including VAT, and we begin by checking whether the building is listed.

From £745 (VAT included)

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  • £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 side return 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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    House extension under construction with scaffolding, new glazed doors and building materials

    Side return extension drawings in the City of London: what is realistic

    A side return belongs to the Victorian terrace: a back addition, a strip of yard beside it, a neighbour's wall on the far side. The City has few streets like that. Its 4,914 households sit mostly in flats, offices converted to flats, and estates, and for those a side return simply does not exist.

    So the honest first answer to most City enquiries is that the work you want is something else: a flat refurbishment, a rear terrace, or alterations inside a listed block. We say so at the start, before any fee is paid. For the genuine side return, usually a small house in one of the older lanes, we draw it in full.

    Brick house being extended, with a wide new opening supported over the ground floor

    Local figures for City of London

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Households living in a house2 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Households4,914Census 2021 (21 March 2021)nomisweb.co.uk
    Conservation areas28 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries637 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Article 4 directions1 Article 4 directions published by the council—planning.data.gov.uk
    Scheduled monuments53 scheduled monuments intersecting the LPA boundary (Historic England)—planning.data.gov.uk
    Householder decisions1 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications granted100 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications decided in time100 % decided within 8 weeks or an agreed extended period1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Domestic gardens share of land (GLUD 2005)0.1 % of land that is domestic garden (GLUD 2005)2005data.london.gov.uk
    Party Wall etc. Act 1996 s3(2)(a)Party structure notice at least 2 months before work—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 City of London
    The 45-degree test in planTest used in daylight assessments: 45 degrees (plan and elevation)A

    The 45-degree test in plan

    A line from the middle of the neighbour's nearest window: the extension should stay behind it.

    A · Test used in daylight assessments
    45 degrees (plan and elevation)

    Conservation areas and listed buildings decide the route

    The City has 28 conservation areas and 637 list entries, a very high density for such a small area. It also holds 53 scheduled monuments, and 1 Article 4 direction. A house here is far more likely to be protected than not, so the permitted development route is rarely open.

    The Party Wall etc. Act sets the timing for a new boundary wall: Line-of-junction (new wall) notice at least 1 month before work. In a listed or monument-adjacent setting, we also expect questions from the council's conservation team about every junction and material, which is why the drawings carry more detail than a suburban set would.

    Barbican and other estates

    Many City homes are on estates managed under their own rules. The Barbican is the best known: the council's Barbican Estate Listed Building Management Guidelines: Volume I Introduction and Volume II Residential (SPD) controls what residents may change. If your home is there, a side return is not the issue. The question is what the guidelines allow at all.

    We read the relevant guideline volume before accepting an estate job, then tell you whether a planning application is worth preparing. Saving you a fee on an application that cannot succeed is part of the service. Our planning drawings page describes what a full application package contains when it is worth making.

    A very small decision record

    Because the City decides so few householder cases, its statistics say little. The single application in the period was granted, and decided in time, which gives 100 per cent on both measures. That is one case, not a trend, and we do not rely on it.

    What it does tell us is that officers here spend much of their time on commercial and heritage cases, and a householder application may be read by someone whose daily work is on a very different scale. We write the supporting notes in plain language and show the extension in context with the adjoining buildings.

    Land, gardens and party walls in a dense area

    Domestic gardens cover 0.1 per cent of the City's land, so a yard beside a house is a rarity and its ownership is worth confirming on the title. Our location and block plans service marks the red line.

    Where a new wall meets a neighbour's, the notice process applies in full. Cutting into an existing shared wall needs a longer period: Party structure notice at least 2 months before work. Our party wall notices page explains how we prepare them.

    Price and what you receive

    A set for a City house includes existing and proposed plans, elevations, a section through the extension and the boundary, and the location and block plans. From £745 including VAT, fixed before you commit, with the council's fee extra.

    Every sheet is checked by a second chartered architectural technologist, and we redraw free until approval if the council asks for amendments. For other work in the borough, see architectural drawings in the City of London, or compare the same service in Westminster and Camden.

    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.
    Finished white-rendered rear house extension with large glazed doors
    Every side considered
    Flick across the turntable to spin it.

    Other services in City of London

    Side return extension drawings nearby

    Questions

    Can I build a side return extension in the City of London?

    Possibly, if you own a house. Only 2 per cent of City households do, and most are protected by conservation area or listing rules.

    Is my City property likely to be listed?

    The City has 637 list entries and 28 conservation areas. We check the address on the national list before quoting.

    What if I live on the Barbican estate?

    The Barbican Estate Listed Building Management Guidelines: Volume I Introduction and Volume II Residential (SPD) sets the limits on alterations. We read them first and advise whether an application is worth making.

    How much are side return extension drawings in the City of London?

    From £745 including VAT, fixed before you commit. 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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