020 7864 7245Request a fixed quote

Harrow, London

Garden room drawings in Harrow

Harrow's Residential Design Guide sets out where an outbuilding should sit and how tall it should be, and gardens take up a large share of the borough's land. Garden room drawings in Harrow start at £495 including VAT, with the design tested against the guide before it is drawn up.

From £495 (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 garden room 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
    Finished white-rendered rear house extension with large glazed doors

    What Harrow's Residential Design Guide asks for

    The council's Residential Design Guide SPD says an outbuilding should sit in the final quarter of the garden, normally two metres from the boundaries, with a height up to four metres for a dual-pitch roof or three metres otherwise. Within two metres of a boundary it recommends two and a half metres high. The figures in the guide read 2 m from boundary; 4 m / 3 m / 2.5 m, and they apply as guidance whenever a room needs consent.

    Those heights closely echo the national outbuilding rule, so a well-sited room can often satisfy both at once. We lay the guide's pattern over your plot: the back quarter of the garden marked out, the two-metre offsets drawn, and the roof pitched to stay inside the height that suits your position.

    Two-storey rear extension under construction on a semi-detached house

    Local figures for Harrow

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Outbuildings should sit in the final quarter of the garden, normally 2 metres from boundaries with a height up to 4 metres (dual pitch) or 3 metres otherwise; within 2 metres of a boundary, 2.5 metres high is recommended.2 m from boundary; 4 m / 3 m / 2.5 m—harrow.gov.uk, Residential Design Guide SPD 2010, p.50, para 6.78
    Domestic gardens share of land (GLUD 2005)34.7 % of land that is domestic garden (GLUD 2005)2005data.london.gov.uk
    Green Belt share of the council area22 % of council area covered by green-belt polygons—planning.data.gov.uk
    Conservation areas31 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries295 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Households living in a house65.4 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Average price, detached1,206,272 GBP2026-07publicdata.landregistry.gov.uk
    Average price, semi-detached663,954 GBP2026-07publicdata.landregistry.gov.uk
    Householder decisions917 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications granted81.7 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications decided in time93.7 % decided within 8 weeks or an agreed extended period1 July 2025 - 30 June 2026assets.publishing.service.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 Harrow
    Single-storey rear extension: the permitted development limitsDepth beyond the original rear wall: 3 m (attached) / 4 m (detached) beyond the original rear wall, single storey. Maximum height: 4 m. Within the zone near the boundary: Eaves no higher than 3 m where within 2 m of the curtilage boundary. Larger extension under prior approval: 6 m (attached) / 8 m (detached), single storey, height max 4 m; not on article 2(3) land or an SSSIABCD

    Single-storey rear extension: the permitted development limits

    The house in section with a rear extension; the dashed lines mark the zone near the boundary.

    A · Depth beyond the original rear wall
    3 m (attached) / 4 m (detached) beyond the original rear wall, single storey
    B · Maximum height
    4 m
    C · Within the zone near the boundary
    Eaves no higher than 3 m where within 2 m of the curtilage boundary
    D · Larger extension under prior approval
    6 m (attached) / 8 m (detached), single storey, height max 4 m; not on article 2(3) land or an SSSI

    Deep gardens and plenty of options

    Domestic gardens cover 34.7 per cent of Harrow's land in the national survey, and 65.4 per cent of households live in a house or bungalow. Detached homes average 1,206,272 pounds and semi-detached homes 663,954 pounds. Many Harrow houses therefore come with a deep rear garden and a lot of options.

    Generous plots tempt owners to build big. The national coverage cap is half the curtilage, and a larger room attracts closer scrutiny near boundaries, so we usually propose a size that serves the use and leaves room for the garden. If you want more than the limits allow, a householder application is available and we say plainly what the guide will make of it.

    Green Belt and heritage in Harrow

    Green Belt covers 22 per cent of the borough. Green Belt is not one of the designations that limit Class E outbuilding rights, but it can matter for plots that border open land, so we confirm it. The borough also lists 31 conservation areas and 295 listed entries.

    A conservation area stops an outbuilding standing between the side wall and the boundary, and a listed house removes outbuilding rights from its grounds. Neither blocks a room at the back of a typical semi, and we confirm which applies at the start. Our location and block plans show the designation edges against your boundaries.

    Building to the guide in practice

    Siting a room in the last quarter of a deep Harrow garden brings practical costs. Power and drainage run a long way from the house, and a path is needed so the room is usable in winter. We note the service route on the plan, and where a trench would pass under tree roots we flag it for your builder before work starts.

    The guide's two-metre offset leaves a strip along the fence, which is useful for maintenance and for a planted screen. Where a neighbour's garage or shed already stands on the boundary, a lower roof on that side keeps the building in proportion. The elevations show each of these decisions, and the section shows the floor build-up and insulation so the builder can price accurately from day one. The plan states the floor area as well, so the officer can see the room's scale without measuring.

    Route to a decision and the council's pace

    Where rights are intact we prepare a Lawful Development Certificate submission; Harrow decided 461 certificate applications of all kinds in its latest return. Otherwise we draw a householder application, as set out on our planning drawings page.

    The council took 917 householder decisions in the latest year, granted 81.7 per cent of them and decided 93.7 per cent on time. Those figures cover all householder work in the borough and do not forecast any single case.

    Fee and next step

    Our set costs a fixed fee from £495, VAT included, and any council fee is paid separately. Send your address and the intended use through the form above. For house works, see our rear extension drawings in Harrow, or visit architectural drawings in Harrow for every local service.

    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.
    House extension under construction with scaffolding, new glazed doors and building materials
    Every side considered
    Flick across the turntable to spin it.

    Other services in Harrow

    Garden room drawings nearby

    Questions

    Where should a garden room sit in a Harrow garden?

    The Residential Design Guide recommends the final quarter of the garden, normally two metres off the boundaries.

    How tall can a garden room be in Harrow?

    The guide's pattern is 2 m from boundary; 4 m / 3 m / 2.5 m, matching the national limits. Closer than two metres to a boundary, the lower height applies.

    Does Harrow's Green Belt affect my back garden?

    Normally not, as Green Belt does not remove Class E outbuilding rights. We check plots that border open land.

    What do garden room drawings cost in Harrow?

    From £495 including VAT, fixed before we start.

    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