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Hounslow, London

Velux loft conversion drawings in Hounslow

Velux loft conversion drawings in Hounslow start at £695 including VAT. Hounslow's residential extension guidance says rooflights should respect the size and position of the windows below, and several units on the front slope may be refused. We use that as the first constraint on the roof plan.

From £695 (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 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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    Slate-clad roof extension on a yellow-brick London terraced house

    What Hounslow's extension guidance says about rooflights

    The council's Residential Extension Guidelines say rooflights should respect the size and position of the house's windows, and that several on the front slope may be refused. The guidance is a design test, not a number, so an officer reads it against the elevation you submit.

    That drives the layout. We align each unit with the window or the gap below it, keep front units to one at most, and put the larger lights on the rear slope. On a typical Hounslow semi that still delivers good daylight to a bedroom and a bathroom.

    The borough's wider design document is the Character, Sustainability and Design Codes SPD, and we read it alongside for the character of each area. Permitted development does not oblige you to follow either, but a scheme that does is easy to defend.

    A short example shows how it works. If the landing window sits at the centre of the front elevation, a single rooflight above it, the same width, reads as part of the same composition. Two lights flanking it would not. That is the sort of judgement an officer is applying when guidance talks about size and position.

    Converted loft bedroom with roof windows and a Juliet balcony

    Local figures for Hounslow

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Conservation areas33 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries519 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Grade I listed entries32 list entries—planning.data.gov.uk
    worldHeritageSites1 World Heritage Sites intersecting the LPA boundary—planning.data.gov.uk
    Article 4 directions3 Article 4 directions published by the council—planning.data.gov.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
    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 Hounslow

    Householder applications by street in Hounslow

    Streets in Hounslow with the most householder applications, and the share approved
    StreetApplicationsApproved
    Firs Drive3761%
    Wood Lane3259%
    Park Drive3169%
    Parkwood Road2859%
    Worton Road2758%
    Arnold Crescent2654%
    Popes Lane2483%
    St Stephens Road2477%
    Whitton Dene2450%
    Harewood Road2378%
    Princes Avenue2382%
    Spring Grove Road2355%
    Fern Lane2268%
    Netheravon Road2273%
    North Hyde Lane2255%
    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.
    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

    Heritage: Chiswick, Brentford and the older centres

    Hounslow has 33 conservation areas and Historic England lists 519 entries, including 32 at Grade I. The borough boundary also touches 1 World Heritage Site. Only 3 Article 4 directions are published, so the heritage work here is mostly about conservation areas and listings rather than directions.

    That is a useful difference for owners. A house in Chiswick or Brentford may be inside a conservation area with no direction, so the rooflight right survives but the design faces closer scrutiny. We read the appraisal for the area as well as the map.

    If your roof keeps its rights, a Lawful Development Certificate records it. If not, the same drawings go through planning drawings in Hounslow.

    Velux loft conversion drawings in Hounslow: decisions and prices

    The council decided 689 householder applications in its latest year and granted 78.5 per cent, which is on the cautious side. It was quick, though, with 97.8 per cent decided in time. A complete first submission is therefore worth the effort.

    A terraced house averages 611,320 pounds here and a semi 716,213 pounds. These are borough averages, not valuations, and the grant rate describes every householder type, not your roof.

    Hounslow has 6 registered parks and gardens, and roofs visible from them can attract comment. We check the sightlines when your house is close to one.

    Build-up, stairs and escape

    Under the slope every centimetre of insulation costs headroom. New windows have to meet: 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. We draw the roof build-up on the section so you can see the clear height before work begins.

    Where the stair cannot reach full height the guidance permits: 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). The escape rooflight must provide: 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. Flight-path noise affects parts of Hounslow, and the construction we show gives an acoustic specialist something to work from.

    Detail for building control is in our building regulations drawings in Hounslow.

    Fixed fee and related pages

    The fee is £695 including VAT, fixed before you commit. A second chartered technologist checks every sheet and we redraw free if the council asks for changes.

    If you need more room, see dormer loft conversion drawings in Hounslow or the comparison at loft conversion drawings in Hounslow. The borough summary is architectural drawings in Hounslow, and the national guide is Velux loft conversion drawings.

    If the survey shows the roof is too low for a comfortable room, we say so before you spend on planning fees, and show what a dormer would add.

    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.
    Brick cottage with a tiled roof, chimneys and a front dormer window
    Storey by storey
    Move up and down — the car travels between floors.

    Other services in Hounslow

    Velux loft conversion drawings nearby

    Questions

    Can I have several rooflights on the front slope in Hounslow?

    The council's guidelines say several on the front slope may be refused, so we keep to one or none and use the rear slope.

    Does the World Heritage Site affect my roof?

    Hounslow has 1 World Heritage Site, and houses near it can face extra care on roof visibility. We check proximity.

    How much do the drawings cost?

    From £695 including VAT.

    What is the rooflight projection limit?

    Roof alterations (e.g. rooflights) may not protrude more than 0.15 m beyond the roof plane.

    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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