020 7864 7245Request a fixed quote

Barnet, London

Side return extension drawings in Barnet

Side return extension drawings for a Barnet house start at £745 including VAT. Barnet writes a number into its guidance for this exact extension: 2 m on the boundary. Every Barnet side return starts from that line, so the drawings do too.

From £745 (VAT included)

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

Request a fixed quote

We use it to check conservation areas and constraints.
Pick the council that decides your application.
A few lines: what you want to build, and anything the council has already said.
Add photos or drawings

Drop files here or choose from your device

PDF, JPG, PNG, DWG · up to 10 files, 90 MB in total

    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.

    Request a fixed quote
    House extension under construction with scaffolding, new glazed doors and building materials

    Side return extension drawings in Barnet and the boundary height rule

    The rule sits in Sustainable Design and Development Guidance SPD, Part 4: Guidance on residential extensions and alterations. It says that a side return, which the guidance calls an outrigger extension, may fill the full width and length of the gap but should be no higher than 2 m on the boundary, measured from the applicant's side. The wider guidance supports the Barnet Local Plan 2021-2036, adopted in 2,025, so an officer reading your application will test the side return against both documents together.

    Barnet's own wording leaves two questions open, and we settle both on paper. First, how the height is read where the boundary wall steps or the neighbour has already extended. Second, how the roof edge is detailed where it meets the shared boundary. We show the answer as a dimensioned section, because a labelled drawing is easier for a case officer to accept than a paragraph of argument in a cover letter.

    Measuring from your side matters more than it looks. If your garden is lower than next door's, the wall you can see from your own kitchen is taller than the wall the neighbour sees, and the opposite holds if you are the higher plot. We take levels on both sides of the boundary in the survey and show the measured height on the elevation, so the officer can check the rule without reaching for a scale rule.

    A common consequence is a flat or very shallow monopitch roof rising away from the boundary. The glass sits on the inner side, the boundary wall stays low, and daylight reaches the middle of the house. We draw the roof falling toward the boundary rather than toward the garden, and we label the boundary height on the section so the rule is visibly met.

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

    Local figures for Barnet

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Side-return (outrigger) extensions can fill the full width and length of the side return but should be no higher than 2 metres on the neighbouring boundary, measured from the applicant's side.2 m on the boundary—barnet.gov.uk, SDDG SPD Part 4 (extensions), p.14, paras 4.46-4.49
    Householder decisions1,361 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications granted80.2 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications decided in time95.1 % decided within 8 weeks or an agreed extended period1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder appeals allowed50.6 % of householder appeals alloweddecision dates 1 Jul 2021 to 30 Jun 2026assets.publishing.service.gov.uk
    Conservation areas16 named conservation areas published by the council—planning.data.gov.uk
    Article 4 directions15 Article 4 directions published by the council—planning.data.gov.uk
    Tree preservation orders718 tree preservation orders published by the council—planning.data.gov.uk
    Average price, terraced634,437 GBP2026-07publicdata.landregistry.gov.uk
    Class A, para A.1(j)Side extension: single storey, max 4 m high, max half the width of the original house—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 Barnet

    Householder applications by street in Barnet

    Streets in Barnet with the most householder applications, and the share approved
    StreetApplicationsApproved
    Wolmer Gardens4282%
    Hampden Way3686%
    Oakleigh Park South3677%
    Marsh Lane3591%
    Millway3493%
    Sturgess Avenue3494%
    Uphill Road3273%
    Chanctonbury Way3190%
    Oakleigh Road North3079%
    Woodlands3076%
    Laurel Way2976%
    Mount Pleasant2880%
    Arlington Road2780%
    Berkeley Crescent27100%
    Longland Drive27100%
    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.
    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)

    Barnet planning figures for householders

    Barnet decided 1,361 householder applications in its latest year, granting 80.2 per cent, with 95.1 per cent decided in time. Refusals can be tested: appeals over five years show 50.6 per cent of 413 householder appeals allowed, so about half the refusals taken that far were overturned by the Planning Inspectorate.

    The borough holds 16 conservation areas, 15 Article 4 directions covering 48 separate areas, and 718 tree preservation orders. A side return rarely touches a tree, but the neighbour's tree can sit close to the new foundation, and we mark it on the plan whenever it does.

    52.5 per cent of households live in a house or bungalow. A terraced house averages £634,437, and average prices have moved -4.9 per cent over twelve months. Domestic gardens take 28.1 per cent of the borough's land, and there is Green Belt on 28 per cent of it.

    Permitted development, party walls and energy limits

    Permitted development does not always cover this extension. The limit reads: Side extension: single storey, max 4 m high, max half the width of the original house. Eaves near the boundary are capped: Eaves no higher than 3 m where within 2 m of the curtilage boundary. The route is closed altogether on protected land, since No side extensions under PD on article 2(3) land (conservation areas etc.).

    Barnet's prior approval record for larger home extensions shows how often the shortcut fails: 18 granted, 103 refused. For most Barnet side returns a householder application is the better route, and our planning drawings in Barnet set is built for it.

    On energy, Windows, roof windows, rooflights and doors in an extension should not exceed 25% of the extension floor area plus the area of openings removed or covered. For fabric, the figures are: 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. A rooflight along the boundary side is attractive to the eye and expensive in glazing area, so we check the percentage against the floor area while the design can still change.

    Cost, fees and the other drawings you may need

    A side return drawing set is £745 including VAT, fixed before you commit, and the council's householder fee of £548 is paid separately to Barnet. If the council asks for changes, we redraw at no charge.

    The wall beside the side return is usually shared. A new wall on the line of junction needs this: Line-of-junction (new wall) notice at least 1 month before work. Work to an existing shared wall needs this: Party structure notice at least 2 months before work.

    Many owners combine the side return with a deeper kitchen, which is why we also draw rear extension drawings in Barnet. Neighbours across the border in Brent work to a different set of dimensions, which you can compare in side return extension drawings in Brent.

    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 Barnet

    Side return extension drawings nearby

    Questions

    What is Barnet's height limit for a side return extension?

    The guidance rule is 2 m on the boundary, measured from the applicant's side, in Sustainable Design and Development Guidance SPD, Part 4: Guidance on residential extensions and alterations.

    Do I need planning permission for a side return in Barnet?

    Often yes. The permitted limit is: Side extension: single storey, max 4 m high, max half the width of the original house, and it does not apply in conservation areas.

    How many Barnet householder appeals succeed?

    50.6 per cent of 413 decided householder appeals were allowed over five years. Each case turns on its own drawings.

    What is the price for side return drawings in Barnet?

    From £745 including VAT, fixed before you commit.

    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.

    Request a fixed quoteCall 020 7864 7245WhatsApp