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Hillingdon, London

Garden room drawings in Hillingdon

Hillingdon's Local Plan gives owners a clear rule of thumb for outbuildings, and the borough also protects a large number of trees. Garden room drawings in Hillingdon start at £495 including VAT, drawn to the Local Plan's outbuilding policy and checked against the borough's tree and Article 4 layers.

From £495 (VAT included)

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  • £2m PI insured
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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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    Brick house being extended, with a wide new opening supported over the ground floor

    The Local Plan's outbuilding policy and its size guide

    Hillingdon's Local Plan Part 2 sets out in its development management policy on outbuildings that, as a general guide, an outbuilding should be no greater than 30 square metres, must be incidental to the house, and may not contain a bedroom, bathroom or kitchen. It is a guide for applications and not a permitted-development limit, but it tells you what the council expects to see.

    We design to that figure by default. A room of that size works well as an office, gym or studio, and we show the floor area on the plan so the officer can check it at a glance. If you need more space, we explain what the policy will make of it before you commit, and a larger building can still be argued as a householder application.

    Finished white-rendered rear house extension with large glazed doors

    Local figures for Hillingdon

    Figures with their unit, period and source
    MeasureValuePeriodSource
    As a general guide an outbuilding should be no greater than 30 square metres, must be incidental, and may not contain a bedroom, bathroom or kitchen (Policy DMHD 2).30 square metres—hillingdon.gov.uk, Local Plan Part 2 DM Policies 2020, p.133, para A1.34 and Policy DMHD 2
    Tree preservation orders731 tree preservation orders published by the council—planning.data.gov.uk
    Green Belt share of the council area42 % of council area covered by green-belt polygons—planning.data.gov.uk
    Article 4 directions150 Article 4 directions published by the council—planning.data.gov.uk
    Conservation areas33 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries436 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Households living in a house68.9 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Average price, detached941,938 GBP2026-07publicdata.landregistry.gov.uk
    Householder decisions1,147 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications granted90.2 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications decided in time94.3 % 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 Hillingdon
    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

    Trees, Green Belt and Article 4

    The borough protects 731 tree preservation orders, which is why we ask for the position of every tree near the proposed room. A foundation near a protected tree can need root-protection details and, in some cases, consent. Green Belt covers 42 per cent of Hillingdon, and plots at the edge of open land need a closer look than a suburban garden does.

    Hillingdon also publishes 150 Article 4 directions, 33 conservation areas and 436 listed entries. A direction can remove outbuilding rights, so we read the wording that covers your address and tell you what it takes away, if anything.

    What the drawings must show in Hillingdon

    Because the policy rules out a bedroom, bathroom or kitchen, the floor plan has to match the policy. We draw a single open room with storage, and where you want a washbasin or a toilet we say clearly what that does to the application. A building regulations drawings set is added if the room is large enough or contains sleeping space, which falls outside the exemption.

    The block plan marks every tree, the position of services and the distance to each boundary. A measured building survey is available if the garden is large or sloping and the fences are uncertain.

    Siting, trees and the retained garden

    On a wide or deep garden a room has plenty of choices, and protected trees often make the decision. We survey the trees, record their crown spread and place the building outside the root zone wherever the plot allows. Where a tree is close, a pad or screw foundation avoids deep digging and is drawn into the section.

    Because the policy asks for an incidental building, we keep the interior simple: one open room, storage and a small entrance. Heating, lighting and power are listed on the plan so your builder can price them once. If you plan a covered seating area beside the room, it counts towards the footprint and is shown on the block plan with its dimensions.

    Location matters for neighbours as well. A room placed at the far end of the garden affects fewer windows than one beside the boundary, and we show both options in 3D visuals when the choice is close.

    A borough of houses and gardens

    Households living in a house or bungalow account for 68.9 per cent of the borough and 56.6 per cent own their home. Detached homes average 941,938 pounds and semi-detached homes 583,573 pounds. Domestic gardens cover 18.6 per cent of the land.

    The council decided 1,147 householder applications in the latest year, granted 90.2 per cent and decided 94.3 per cent on time. These borough-wide figures cover all householder work and do not predict any single case.

    Certificate or application, then cost

    Where rights are intact, a Lawful Development Certificate records the room as lawful; the council decided 529 certificate applications of all kinds in its latest return. Otherwise we prepare a householder application, set out on our planning drawings page.

    The set is a fixed fee from £495 with VAT included, and any council fee is extra. Send your address and use through the form above. For work on the house, see rear extension drawings in Hillingdon, or architectural drawings in Hillingdon for the full list.

    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.
    Two-storey rear extension under construction on a semi-detached house
    Every side considered
    Flick across the turntable to spin it.

    Other services in Hillingdon

    Garden room drawings nearby

    Questions

    How large can a garden room be in Hillingdon?

    The policy suggests no more than 30 square metres as a general guide. The national permitted-development limits also apply.

    Can a Hillingdon garden room have a bathroom?

    The policy says an outbuilding may not contain a bedroom, bathroom or kitchen, so adding one changes the route.

    Do tree preservation orders affect my garden room?

    They can. The borough protects 731 orders, and a foundation near a protected tree may need extra detail or consent.

    What is the price of garden room drawings in Hillingdon?

    From £495 including VAT, fixed up front.

    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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