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Hillingdon, London

Velux loft conversion drawings in Hillingdon

Velux loft conversion drawings in Hillingdon cost £695 including VAT. Hillingdon decided 1,147 householder applications in its latest year, and it has published 150 Article 4 directions. Both facts shape a Velux scheme: plenty of precedent, and a real need to check your address.

From £695 (VAT included)

  • MCIAT chartered
  • £2m PI insured
  • LABC Partnered
  • 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 velux loft conversion 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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    Converted loft bedroom with roof windows and a Juliet balcony

    A borough with a lot of precedent

    Hillingdon granted 90.2 per cent of those 1,147 householder applications, and 94.3 per cent were decided in time. With that volume, officers have seen every kind of roof alteration, and the planning register shows what has been accepted on your road and the next.

    We search that register before drawing, and set your scheme against recent roof decisions nearby. It is the nearest thing to a local rule when the council has published no figure for rooflights, and it often settles questions about how many units a front slope will tolerate.

    These are borough-wide figures across all householder work. They help us plan time and care, and they are not a forecast.

    A volume of work like that has a practical benefit for clients. Officers are used to roof drawings, so they notice an incomplete set at once. Ours always show the existing and proposed roof in plan, section and elevation on matching scales, with the rooflight sizes dimensioned.

    Brick cottage with a tiled roof, chimneys and a front dormer window

    Local figures for Hillingdon

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Article 4 directions150 Article 4 directions published by the council—planning.data.gov.uk
    Article 4 direction areas150 Article 4 direction area polygons 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
    Green Belt share of the council area42 % of council area covered by green-belt polygons—planning.data.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
    GPDO Sch 2 Pt 1 Class C, para C.1(b)Roof alterations (e.g. rooflights) may not protrude more than 0.15 m beyond the roof plane—legislation.gov.uk
    Approved Document K 2013, para 1.13, Diagram 1.4Loft conversions where 2.0 m cannot be achieved: 1.9 m at the centre of the stair, 1.8 m at the side (half width)—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
    Loft enlargement in section: the permitted development limitsExtra roof volume allowed: 40 m³ (terrace house) / 50 m³ (any other house) additional roof volume. Set-back from the eaves: Original eaves maintained; enlargement set at least 0.2 m from the eaves measured up the roof slope, so far as practicable (not required for hip-to-gable or roofs joining a rear/side extension). Height limit: No part higher than the highest part of the existing roofABC

    Loft enlargement in section: the permitted development limits

    A dormer on the rear slope, with the limits that decide whether it needs planning permission.

    A · Extra roof volume allowed
    40 m³ (terrace house) / 50 m³ (any other house) additional roof volume
    B · Set-back from the eaves
    Original eaves maintained; enlargement set at least 0.2 m from the eaves measured up the roof slope, so far as practicable (not required for hip-to-gable or roofs joining a rear/side extension)
    C · Height limit
    No part higher than the highest part of the existing roof

    Article 4 directions and Green Belt in Hillingdon

    The 150 directions are mapped as 150 areas, and the borough has 33 conservation areas and 436 listed entries. About 42 per cent of the area is Green Belt.

    The overlaps are what catch owners out. A house in a village within the Green Belt may also be in a conservation area and covered by a direction, so three layers apply to a single roof. We lay them over your address and tell you what remains.

    Where rights survive, a Lawful Development Certificate is the quick route. Where they do not, the drawings go through planning drawings in Hillingdon.

    Velux loft conversion drawings in Hillingdon: the roof detail

    Interwar and postwar semis are common here, with 68.9 per cent of households in a house or bungalow. A semi averages 583,573 pounds, a detached house 941,938 pounds, which gives the loft room a real value.

    On permitted development the rooflight rule is: Roof alterations (e.g. rooflights) may not protrude more than 0.15 m beyond the roof plane. Side-slope windows need: Side roof-slope windows obscure-glazed and non-opening below 1.7 m. Large detached houses often have a long side slope, so that second rule decides whether a bathroom can have daylight.

    Where the roof stair has to move, the first-floor plan changes with it: a bedroom may shrink or a landing may grow. We test those knock-on effects early, before committing to a stair position.

    Stair, fire and smoke alarms

    A loft stair has to fit within the existing house. Where full headroom fails, the Approved Document accepts: Loft conversions where 2.0 m cannot be achieved: 1.9 m at the centre of the stair, 1.8 m at the side (half width). We test the stair on the measured section before we fix the layout.

    The new storey also brings: New storey above 4.5 m by loft conversion: protect the full escape route with fire-resisting doors (min E 20) and partitions (min REI 30). Alarm provision is covered too: All dwellings: fire detection and alarm system minimum Grade D2 Category LD3 (BS 5839-6), mains-operated smoke alarms to BS EN 14604. We put all of this on the plans so the building regulations drawings in Hillingdon follow without rework.

    Because the Heathrow flight paths cross parts of the borough, owners sometimes ask about noise. Rooflights are a small part of a roof's acoustic performance, and we show the construction so a specialist can add what is needed.

    Fees, review and next steps

    We charge a fixed £695 including VAT. A second MCIAT chartered technologist checks each sheet, and revisions the council asks for are redrawn free. Before any fee is paid we tell you whether we expect a certificate or a full householder application, and why.

    If the slope is too shallow for rooflights, see dormer loft conversion drawings in Hillingdon. The whole range is at loft conversion drawings in Hillingdon; the borough guide is architectural drawings in Hillingdon, and the national page is Velux loft conversion drawings.

    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.
    Rear view of brick terraced houses in London with slate roofs and chimney stacks along the shared roofline
    Storey by storey
    Move up and down — the car travels between floors.

    Other services in Hillingdon

    Velux loft conversion drawings nearby

    Questions

    Which parts of Hillingdon are covered by Article 4 directions?

    The council has published 150 directions across 150 areas. We check your address against the register.

    Does Green Belt affect rooflights?

    Rarely, since rooflights add no bulk, but 42 per cent of the borough is Green Belt, so we check the address.

    How much do the drawings cost?

    From £695 including VAT.

    What escape window is needed?

    Escape window: unobstructed openable area at least 0.33 m², at least 450 mm high and 450 mm wide, bottom of opening no more than 1100 mm above floor.

    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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