Skip to main content
Trusted Loft Conversions
Velux skylights installed in a loft conversion
Most Affordable Loft Conversion

Velux Loft Conversion Specialists

A Velux loft conversion costs between £15,000 and £25,000 in the UK — the most affordable option as it requires no structural changes to the roofline.

A Velux loft conversion works within your existing roof structure, adding roof windows for natural light and ventilation. The fastest and most cost-effective route to a new bedroom — typically Permitted Development.

From £15,000
Timescale: 4–6 weeks

FREE NO-OBLIGATION ESTIMATE

Get Your Free Estimate

What is a Velux Loft Conversion?

A Velux loft conversion — sometimes called a rooflight conversion — uses the existing roof structure without altering its shape or adding any dormer extensions. Velux roof windows are fitted flush within the roof slope, bringing in daylight and providing ventilation while keeping the external appearance of your home unchanged.

Because the existing roof structure is largely retained, this is the quickest and least expensive type of loft conversion. There is minimal scaffolding, reduced structural work, and the build programme is typically four to six weeks. It is also the conversion type least likely to require any planning permission.

A Velux conversion is most effective where the existing roof already has a steep pitch — ideally 35 degrees or more — giving good natural headroom. If your ridge height is marginal, we will advise whether a Velux conversion can still deliver a comfortable, habitable room or whether a dormer would better suit your needs.

Key Benefits of a Velux Conversion

Most Affordable

Starting from £15,000, a Velux conversion is the most budget-friendly way to add a habitable loft room.

Minimal Disruption

No major structural alterations, less scaffolding, and a faster build means less impact on your day-to-day life.

Fast Completion

Most Velux conversions are complete in 4–6 weeks — the quickest of all loft conversion types.

Usually No Planning

Rooflights flush with the slope almost always fall within Permitted Development — no planning fees or delays.

Is a Velux Conversion Right for My Home?

A Velux conversion works best on properties where the existing roof structure already provides reasonable headroom. Check the following:

  • Roof pitch of 35° or steeper — provides good natural headroom without structural alteration
  • Ridge height of at least 2.5 m above existing ceiling joists (we measure on survey)
  • Good existing roof condition — rafters and roof covering in sound condition
  • No desire to significantly alter the external roof line
  • Budget-conscious project where maximum affordability is the priority
  • Urgency — Velux conversions can be designed, approved, and built in the shortest time

Where headroom is borderline, we will compare a Velux against a dormer and give you an honest recommendation based on your specific property.

What's Included in Every Velux Conversion

Free site survey and headroom assessment
Architectural drawings for building regulations
Permitted Development check and confirmation
Building regulations submission and approval
Structural engineer sign-off on floor joists
All scaffold, materials, and plant
Supply and installation of Velux roof windows
Insulation between and below rafters (warm roof specification)
New structural floor and floor boarding
Stud walls, plasterboard, and first-fix electrics
New staircase and fire-rated landing door
Final clean, snagging, and building regs sign-off

Typical Cost and Timescale

Cost Guide

From £15,000

Full project cost including all planning, structural, and build work. The most affordable loft conversion type available.

Build Programme

4–6 weeks

The fastest of all conversion types. Minimal structural work means a shorter programme and less disruption to your household.

All quotes are fixed-price with no hidden extras.

Frequently Asked Questions

What size Velux windows can I install in a loft conversion?
Velux manufacture roof windows in a wide range of sizes, from compact 55×78 cm units up to large panoramic 114×118 cm windows. The right size depends on your rafter spacing and roof pitch. We recommend as large a window as the structure will allow to maximise light and ventilation. Our survey will specify the optimal sizes and positions for your roof.
Does a Velux loft conversion need planning permission?
In most cases, no. Velux (rooflight) conversions almost always fall within Permitted Development rights because they do not alter the overall shape of the roof or add any volume. The windows must be flush with the roof plane and must not project forward of the roof slope on the principal elevation. We confirm PD eligibility on every survey, and applications to conservation area authorities are handled by our team if required.
Is a Velux conversion suitable for use as a bedroom?
Yes — provided building regulations requirements are met. A habitable Velux loft room needs adequate headroom (at least 2.2 m over a minimum floor area), fire-safe staircase access, appropriate thermal insulation, emergency escape windows, and compliant electrics. We design every Velux conversion to meet these requirements so your new room is legally habitable and comfortable year-round.
What is the minimum headroom needed for a Velux loft conversion?
Building regulations require a minimum of 2.2 m clear headroom over at least part of the habitable floor area. As a practical guide, your existing ridge height should be at least 2.5 m above the existing ceiling joists to achieve this once insulation and new flooring are installed. We check this on our free survey — if your ridge height is marginal we will advise on whether a Velux or a dormer conversion is the better solution.
Can Velux windows be installed in any type of roof?
Velux roof windows are compatible with most pitched roofs with a pitch between 15° and 90°. They are most effective on roofs with a steeper pitch (35°+) where they provide good natural light. Flat or near-flat roofs require specialist flat-roof units. We will assess your roof during the free survey and recommend the best glazing solution for your specific pitch and rafter configuration.

Explore More

Available across London

Related guides

Other services

Start Your Velux Loft Conversion Today

Get a free, no-obligation survey and fixed-price quote — the fastest route to a new bedroom in your home.

Get a Free Estimate →