Velux Loft Conversions
Velux Loft Conversions
City Lofts London designs and builds Velux loft conversions across South West London and Surrey. Also known as a rooflight or skylight conversion, this is the simplest, most affordable way to turn an existing loft into a usable room — adding roof windows to bring in natural light, without altering the shape or structure of the roof itself.
Get a free, no-obligation site survey and fixed-price quote within 48 hours.
Get a free, no-obligation site survey and fixed-price quote within 48 hours.
Contact City Lofts London
Telephone: 020 8898 8299
Address: 12 High Street, Hampton Wick, Kingston upon Thames, KT1 4DB
City Lofts LondonWide Limited. Registered in England and Wales.
Company number 11454709. VAT number 299773521
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What is a Velux loft conversion?
A Velux conversion — also called a rooflight or skylight conversion — installs windows directly into the existing roof slope rather than building out or altering the roof’s shape. “Velux” is technically a brand name (the best-known manufacturer of roof windows), but it’s widely used as the general term for this whole conversion type. Because the structural work is minimal compared to a dormer, hip-to-gable or mansard, it’s typically the fastest and most cost-effective way to convert a loft, provided your existing roof space already has enough headroom to work with.
Best suited to: properties with a high-pitched roof and enough existing headroom at the ridge — commonly older Victorian and Edwardian houses with steep roof pitches, where a dormer or other structural alteration isn’t strictly necessary to create a comfortable room.
Velux vs. dormer: which is right for your loft?
- Velux conversion — no change to the roof’s shape or volume, lower cost, faster build, and in most cases no planning permission required. Best where the existing roof already has good headroom.
- Dormer conversion — adds a box extension to part of the roof, creating more floor space and full head height, but at higher cost and with more structural work involved.
If your roof doesn’t have quite enough existing headroom for a comfortable Velux conversion, we’ll tell you honestly during your free survey — in that case, a dormer or other conversion type may be a better fit, and we’re happy to talk through the alternatives.
Velux Loft Conversion in Isleworth: Case Study
This is a highly technical conversion where the roofline itself wasn’t changing — instead, we’re converting the space within multiple existing roof slopes. The real finesse on the design side was configuring the landing to give access to the new loft bedroom, bathroom and office at the rear, all while navigating the complexities of those multiple slopes. This project is putting every one of our skills of structural calisthenics to the test.
Do I need planning permission for a Velux conversion?
In most cases, no. Velux conversions are usually the easiest loft conversion type to get approved, because they don’t alter the roof’s shape, height or volume, so they typically fall under Permitted Development (PD) rights without needing a full planning application — provided:
- The property isn’t in a conservation area, subject to an Article 4 direction, or a listed building (some conservation areas require rooflights to sit flush with the roof rather than projecting)
- The windows don’t project significantly above the plane of the existing roof slope
- No dormer, extension or change to the roof shape is involved
Even where PD applies, every Velux conversion still requires Building Control approval to confirm the structural work, insulation, fire safety and staircase (where needed) meet current regulations. City Lofts London manages this for you as part of our service.
Velux loft conversion cost guide
| Room size | Typical cost (South West London & Surrey, 2026) |
|---|---|
| Velux conversion (20m²) | £ 30,000+ |
| Velux conversion (30m²) | £ 55,000+ |
Figures are indicative. Industry data typically puts London Velux conversions in the region of £30,000–£45,000 for a 20m² room, rising to £55,000–£65,000 for a larger 30m² space — the most affordable loft conversion type available, and usually the fastest to build. Every quote from City Lofts London is fixed-price, with no hidden extras once the contract is signed.
What’s included in our price: architectural design, structural engineer’s calculations, planning/Building Control applications, steel beams and structural work, insulation, plasterboard and finish, electrics and plumbing first and second fix, staircase, and a full skip and waste clearance.
Our process, start to finish
- Free survey & consultation — we assess your roof and property, discuss layout options and conservation-area or listed-building considerations, and give a same-week ballpark estimate.
- Design & drawings — our in-house architectural team produces layout options and detailed planning/Building Control drawings, matched sympathetically to the existing property.
- Planning & Building Control — we submit and manage the full planning application, Listed Building Consent where relevant, Building Control approval, and any Party Wall Agreements.
- Structural work — the existing rear roof slope is removed and rebuilt as a near-vertical mansard wall with a flat roof, then made weathertight.
- First fix — electrics, plumbing, insulation and staircase.
- Finishing — plastering, flooring, decoration, and final electrics/plumbing fix.
- Sign-off — Building Control final inspection and completion certificate.
Typical timeline: 4–6 weeks on site — significantly faster than a dormer, hip-to-gable or mansard conversion, since the roof structure itself isn’t being altered.
Why choose City Lofts London
- In-house architects, structural engineers and project managers — no subcontracted design
- Fixed-price quotes with no hidden costs
- Full planning permission and Building Control management included
- 25 years’ experience and 100+ completed loft conversions across London
Areas we cover
City Lofts London specialises in Velux loft conversions across South West London and Surrey. In South West London we cover Wandsworth, Putney, Isleworth, Battersea, Balham, Tooting, Wimbledon and Raynes Park; in Surrey and along the London/Surrey border we cover Kingston, Surbiton, Richmond, Twickenham, Teddington, Staines, Ashford and East Molesey, and the surrounding areas.
We also carry out loft conversions in other parts of London, including [West/North London boroughs]. Get in touch to check coverage for your postcode or see our full list of areas.
Frequently asked questions
Is a Velux conversion the same as a rooflight conversion?
Yes — “Velux” is technically a brand name (the best-known manufacturer of roof windows), but it’s widely used as the general term for this whole conversion type, which installs windows into the existing roof slope without altering its shape.
Do I need planning permission for a Velux conversion?
In most cases, no. Because Velux conversions don’t change the shape, height or volume of the roof, they typically fall under Permitted Development. Building Control approval is still required.
How much does a Velux conversion cost compared to a dormer?
Velux conversions are the most affordable loft conversion type, typically £30,000–£65,000 in London depending on room size, compared to £55,000 and upwards for a dormer conversion, since there’s no structural alteration to the roof shape itself.
Is my loft suitable for a Velux conversion?
It depends on your existing headroom and roof pitch — properties with steeper, high-pitched roofs (common on Victorian and Edwardian houses) are usually the best fit. We’ll confirm suitability during your free survey, and suggest an alternative like a dormer if a Velux conversion wouldn’t give you a comfortable room.
How long does a Velux loft conversion take?
Most Velux conversions take 4–6 weeks on site, making it the fastest loft conversion type since the roof structure itself isn’t being altered.
