The conversion guide / velux
Velux Loft Conversions
The simplest, most cost-effective conversion — Velux roof windows added into the existing roof line without structural extensions.
At a glance / 01
Homes with generous existing loft head-height
The roofline / 02
Roof windows are fitted into the existing slope without building a dormer. The original roof profile remains the starting point for the room inside.
Planning / 03
Rooflights that do not enlarge the roof are generally considered under Class C rather than the Class B rules for dormers.
Find your fit
Is this the right conversion for your home?
Bring daylight in. Keep the roofline. Best where the loft already has enough usable head height. Roof windows add daylight but do not themselves create the standing room a dormer can provide.
A Velux loft conversion — sometimes called a roof-light conversion — keeps your existing roof shape and adds Velux windows to bring light into the space.
It's the fastest, cleanest and most budget-friendly conversion, ideal where head-height already exists in the loft.
It may suit
- Homes with generous existing loft head-height
- Chalet bungalows
- Home office or single bedroom conversions
- Conservation areas where roof changes are restricted
01 / The starting point
Bring daylight in. Keep the roofline.
Best where the loft already has enough usable head height. Roof windows add daylight but do not themselves create the standing room a dormer can provide.
Concept Lofts / Roof study
Roof form / illustrationRoof anatomy
What happens to the roofline?
Roof windows are fitted into the existing slope without building a dormer. The original roof profile remains the starting point for the room inside.
Every roof is different. We survey the existing structure before recommending a design.
The planning route
Will I need planning permission?
Do I need planning permission for a Velux or rooflight loft conversion? Fitting rooflights to an existing house roof can often be permitted development, provided the roof's shape is not enlarged and the Class C conditions are met. This is a different route from Class B for a dormer or hip-to-gable enlargement.
The rooflight itself is only part of the assessment. If a proposal also changes the roof's volume or form, it needs to be assessed under the rules relevant to that enlargement, rather than treating the whole loft conversion as simple rooflight work.
Class C rooflight works do not use the Class B 40m³/50m³ dormer allowances or its eaves-setback test. They are householder rights for houses, not an automatic permission for flats or maisonettes. Rights can be restricted by an Article 4 direction or earlier planning condition; listed buildings have separate controls. Unlike Class B roof enlargements, Class C is not automatically excluded simply because a house is in a conservation area.
Under Class C, an alteration must not project more than 0.15m beyond the plane of the original roof slope, measured perpendicular to that slope, or be higher than the highest part of the original roof.
Materials should be similar in appearance to the existing dwellinghouse. Any side-facing window must be obscure glazed and non-opening unless the opening part is more than 1.7m above the room floor.
Check for removed PD rights, listed-building controls and any other local constraints. Building Regulations approval for the loft conversion remains separate from planning.
Do I still need an application?
Even when full planning permission is not needed, we normally recommend applying for a Lawful Development Certificate (LDC) where appropriate. It formally confirms that the proposed work is lawful under permitted development. It is not planning permission and is not legally mandatory simply because work is PD, but it provides useful evidence for your records and a future sale.
We assess your property and loft design, check the relevant permitted development or planning route, prepare drawings and handle the appropriate council submission as part of our design and planning process. No approval can be guaranteed.
Planning and Building Regulations are separate. For more detail, read our loft conversion planning guide or the GOV.UK householder technical guidance. Rules here describe the general position for houses in England; the exact property and proposal must be checked.
Design decisions
The details make the difference.
The right materials, glazing and internal layout should feel like they belong to the home. Options are assessed against the design and any applicable planning conditions.
- 01Roof window size and position chosen around the internal layout
- 02Glazing, blinds and ventilation specified to suit the room
- 03Low-level eaves can work as thoughtfully planned storage
Depending on the design, we can also discuss electric opening rooflights, integrated blinds, solid oak stairs, bespoke storage in the eaves.
Design note / velux
Bring daylight in. Keep the roofline.
We design the roof, stairs and usable space together — not as separate decisions.
Inside the roof
What could the space become?
An existing generous roof can become a light-filled bedroom, study or retreat, with the final use dependent on headroom and Building Regulations.
A measured survey and design consultation will establish what works in your home.
From first visit to finish
A considered route to a finished loft.
- 01 / 06
Assess
Survey the roof and establish whether velux loft conversions suit the house.
- 02 / 06
Design
Develop the layout around roof windows are fitted into the existing slope without building a dormer. the original roof profile remains the starting point for the room inside.
- 03 / 06
Planning / LDC
Check the permitted-development route and consider an LDC where appropriate.
- 04 / 06
Building Regulations
Coordinate structural design, stairs and technical approvals.
- 05 / 06
Build
Turn the agreed drawings into the finished space.
- 06 / 06
Completion
Finish the details and hand over the relevant certificates.
Good questions
Velux Loft Conversions, explained.
How quick is a Velux conversion?
Typically 4–5 weeks on site — the fastest loft conversion type we build.
Are Velux rooflights permitted development?
Many rooflights on houses can qualify under Class C if they stay within the 0.15m projection limit and meet the other conditions. A dormer or other roof enlargement must be assessed separately; we also check that the house still has the relevant PD rights.
Explore another approach
A place to start
Could this be the right conversion for your home?
Tell us about your house. We’ll look at the roof, talk through your plans and advise on a sensible route forward.
Get a free loft assessmentBook a free consultation for your velux loft conversions
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