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Hounslow, London

Garden room drawings in Hounslow

Hounslow's Residential Extension Guidelines set a height guide for garden buildings and ask for a lower roof near a boundary. Garden room drawings in Hounslow start at £495 including VAT, with the roof shaped to that guide and the plot checked against the borough's World Heritage Site, Green Belt and conservation layers.

From £495 (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 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.

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    House extension under construction with scaffolding, new glazed doors and building materials

    The Hounslow height guide for outbuildings

    The Residential Extension Guidelines SPD says outbuilding eaves, and the whole height of a flat-roofed building, should be no higher than three metres, and a ridge no higher than four. Within one metre of a boundary, the height on that side should come down. The guide's figures read 3 m flat/eaves; 4 m ridge, and they apply as guidance whenever the room needs consent.

    The national rule is different: within two metres of a boundary, height is capped at two and a half metres. Where the two do not agree we draw to the stricter figure and show the choice in the section, so a flat-roofed studio near a fence reads as a considered design to the officer.

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

    Local figures for Hounslow

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Outbuilding eaves, and the whole height of a flat-roofed outbuilding, should be no higher than three metres, and a ridge no higher than four metres; within one metre of a boundary the height should be reduced on that side.3 m flat/eaves; 4 m ridge—hounslow.gov.uk, Residential Extension Guidelines SPD 2017, p.28, section 4.8
    worldHeritageSites1 World Heritage Sites intersecting the LPA boundary—planning.data.gov.uk
    Listed building entries519 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Conservation areas33 named conservation areas published by the council—planning.data.gov.uk
    Article 4 directions3 Article 4 directions published by the council—planning.data.gov.uk
    Green Belt share of the council area22 % of council area covered by green-belt polygons—planning.data.gov.uk
    Domestic gardens share of land (GLUD 2005)21.5 % of land that is domestic garden (GLUD 2005)2005data.london.gov.uk
    Households living in a house54 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Householder decisions689 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications granted78.5 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications decided in time97.8 % 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 Hounslow
    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

    A borough with a World Heritage Site

    A World Heritage Site touches the boundary, and Hounslow also lists 519 entries and 33 conservation areas. Most gardens are far from the site itself, but its setting can matter close by, so we check your address against the mapped extent.

    The Article 4 picture is light: the council publishes 3 directions. That helps most owners, since outbuilding rights are usually intact, though we confirm the wording for the one that covers your road.

    East, central and west gardens

    Plots in Hounslow range from narrow terraced gardens to wider suburban ones. Green Belt covers 22 per cent of the borough, and domestic gardens make up 21.5 per cent of the land. Only 54 per cent of households live in a house or bungalow, so many gardens here belong to flats and maisonettes.

    Detached homes average 1,043,294 pounds, semi-detached 716,213 pounds and terraced 611,320 pounds. For a flat with a shared garden, a planning application is needed because outbuilding rights belong to houses, and the freeholder's consent usually comes first.

    Services, drainage and the build-up

    A garden room needs power, and often data and heating. Behind a terrace, the run from the house is short but the garden is narrow, so trenches are tight against the boundary. On a wider suburban plot the run is longer and costs more. We mark the preferred route on the plan and note any drain or manhole in the garden, since building over a public sewer needs the water company's agreement.

    The section shows insulation, a damp-proof course and the floor build-up, and it notes the foundation type you and your builder have agreed. Ground-screw and concrete-pad options are both common, and the right one depends on the soil and on how close the building is to a tree. All of this is on the drawings, so quotes from builders are comparable.

    Drawing the roof right

    Roof choice is where Hounslow's guide earns its keep. A flat roof can reach three metres at the top of the wall, while a pitched one can climb to four at the ridge, so the pitch and the eaves height decide how tall the room looks from next door. We draw both options and show them in 3D visuals beside the neighbouring fence.

    A sedum roof adds weight to the structure and is noted on the section. Where the room sits within a metre of the boundary, the lower height is drawn on that elevation, with the dimension labelled.

    Certificate, application and the council's record

    When rights are intact, a Lawful Development Certificate records the room as lawful; the council handled 445 certificate applications of all kinds in its latest return. Otherwise we prepare a householder application, as set out on our planning drawings page.

    The council decided 689 householder cases in the latest year and granted 78.5 per cent. It decided 97.8 per cent on time. These figures cover all householder work and do not predict a single case.

    Fee and next step

    The set is a fixed fee from £495 with VAT included; any council fee is extra. Send your address and use through the form above. For house works, see loft conversion drawings in Hounslow, or the full list of architectural drawings in Hounslow.

    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 Hounslow

    Garden room drawings nearby

    Questions

    How tall can a garden room be in Hounslow?

    The SPD guide reads 3 m flat/eaves; 4 m ridge, with a lower height close to a boundary.

    Does Hounslow's World Heritage Site affect my garden?

    Only if your home lies within the site or its setting. We check the mapped extent against your address.

    Can a flat owner build a garden room in Hounslow?

    Outbuilding rights belong to houses. A flat needs a planning application, and the freeholder's consent where the lease requires it.

    What do garden room drawings cost in Hounslow?

    From £495 including VAT, fixed before we begin.

    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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