Velux Flat Roof Skylights vs UK Alternatives: Complete Buyer's Guide

Velux is one of the most recognisable names in roof glazing and frequently appears early in any research into flat roof skylights. However, Velux is a broad brand that spans many product types and when it comes specifically to flat roof applications, a growing number of UK manufacturers offer comparable or superior performance, faster delivery and greater choice of size and finish. This guide covers how flat roof skylights work, what to look for when buying, how Velux flat roof products compare to UK alternatives and where to find British-made options with a strong track record.

What Is a Flat Roof Skylight?

A flat roof skylight, also referred to as a rooflight or flat roof window, is a glazed unit installed within or just above a flat roof surface to introduce natural light into the space below. Unlike pitched roof windows, flat roof skylights are designed to be weatherproof without relying on the angled drainage that sloped roof products require. They are among the most popular home improvements in the UK, particularly for kitchen extensions, rear extensions, loft conversions and garden rooms where overhead light makes a measurable difference to how a space feels and performs day to day.

What Are Velux Flat Roof Skylights?

Velux produces a range of flat roof products including their CFP (fixed flat glass) and CVP (curved glass) ranges, as well as modular skylight systems for larger installations. Their flat roof range is designed for low-pitch applications and is available through builders merchants and roofing suppliers across the UK. Velux is a Danish company and their flat roof products are manufactured in Europe and imported into the UK. Lead times and availability depend on the merchant or distributor the order is placed through and their standard range is limited to fixed sizes with no custom or bespoke dimension option.

Manufacturing Origin

Velux flat roof skylights are manufactured in Europe and imported into the UK. UK-made alternatives from Rooflights and Skylights UK are designed and produced in Britain, carry full UKCA certification and are members of Made in Britain, the official certification body recognising products manufactured in the UK.

Delivery Speed

Velux products are typically ordered through a merchant or distributor, which can extend the overall lead time. UK-manufactured flat roof skylights from Rooflights and Skylights UK are dispatched directly within 3 to 4 working days for standard sizes, with free delivery to all UK mainland addresses.

Custom Sizes

Velux flat roof products are available in a fixed range of standard sizes only. UK alternatives from Rooflights and Skylights UK are available in standard sizes from 500x500mm up to 1000x3000mm (internal dimensions), with custom and bespoke dimensions available within 7 to 10 working days. This makes them the appropriate choice for extensions with non-standard roof openings where an off-the-shelf size will not work.

Guarantee

Rooflights and Skylights UK provides a 10-year guarantee on every flat roof skylight as standard. Each unit is individually inspected before dispatch to confirm it matches the specification exactly.

Award Recognition

Rooflights and Skylights UK has been recognised with the Professional Builder Top Product Award in both 2024 and 2025, voted for by tradespeople and builders across the UK. This represents independent recognition of product quality, reliability and value from professionals who specify and install these products daily.

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Frameless Flat Roof Rooflights

Frameless rooflights are precision-fitted with minimal visible edging for a clean, contemporary look. They maximise the glass area, allowing more natural light into the room below and suit modern or minimalist interiors. Available from £165 ex VAT at 500x500mm, in sizes up to 1000x3000mm and in custom dimensions.

Framed Flat Roof Rooflights

Framed rooflights have a defined thermally broken aluminium frame around the glazing, offering a structured finish that integrates cleanly within the roofline. Available from £392 ex VAT in Anthracite Grey (RAL 7016) and Jet Black (RAL 9005) as standard, with other RAL colours available on request.

Roof Lanterns

Roof lanterns are raised, multi-paned glazed structures that draw natural light into a room from multiple angles throughout the day. They carry a genuine architectural presence and are particularly well suited to kitchen extensions and open-plan living areas. Available from £673 ex VAT at 1000x1000mm.

Glazing Type

Choose the glazing option that best suits your room’s lighting, privacy and temperature-control needs.

UK flat roof skylights are available with double or triple glazing across several glass specifications.
Clear Low-E glass: maximises light transmission while retaining heat. The appropriate specification for most residential installations.
Solar control glass: manages heat gain through summer. Recommended for south-facing rooflights or rooms that receive strong direct sun.
Satin privacy glass: allows natural light through while obscuring the view. Well suited to bathrooms and overlooked spaces.
Solar grey glass: tinted glazing that reduces glare while maintaining natural light levels.

U-Value and Thermal Performance

For UK building regulations compliance, rooflights in new builds and extensions typically need to achieve a U-value of 1.6 W/m2K or better. Triple glazed units achieve significantly lower U-values, improving energy performance and reducing heat loss. The U-value of the unit should always be confirmed against specific project requirements and building control conditions before ordering.

Internal Size vs External Size

When ordering a flat roof skylight, always measure the internal roof opening rather than the external upstand dimensions. Most UK suppliers quote internal dimensions. Ordering to external measurements is the most common sizing error and can result in a unit that does not fit the opening correctly.

Planning Permission

Most flat roof skylight installations on domestic properties are covered under permitted development rights and do not require a planning application, provided the installation remains within the existing roofline and meets the relevant height restrictions. Owners of listed buildings or properties within a conservation area should seek written confirmation from their local planning authority before any works commence.

UK-Made Velux Alternatives for Flat Roofs

For homeowners and builders looking for UK-manufactured flat roof skylights with fast delivery, custom sizing and independent award recognition, Rooflights and Skylights UK offers a strong alternative to Velux for flat roof applications.

Designed and manufactured in Britain, UKCA certified and a member of Made in Britain
Standard sizes dispatched within 3 to 4 working days with free UK mainland delivery
Custom and bespoke sizes available within 7 to 10 working days
10-year guarantee on every product, inspected before dispatch
Professional Builder Top Product Award winner in both 2024 and 2025
Framed and frameless designs from 500x500mm to 1000x3000mm
Double or triple glazing including solar control, clear Low-E, solar grey and satin privacy glass
Anthracite Grey and Jet Black frames as standard, with other RAL colours available on request

The full range is available at rooflightsandskylightsuk.co.uk or by contacting the team on 0331 6303 671 for free advice on sizing and specification.

Velux produces specific products for flat roofs including their CFP and CVP ranges. Their flat roof range is limited to fixed standard sizes and is manufactured in Europe. UK-made alternatives offer custom sizing, faster direct delivery and guarantees backed by British manufacturing standards.

The right flat roof skylight depends on the requirements of your project. For UK-manufactured quality with fast delivery and custom sizing, Rooflights and Skylights UK offers framed and frameless rooflights from 500x500mm to 1000x3000mm, with standard sizes dispatched within 3 to 4 working days and a 10-year guarantee on every unit. The brand has been recognised with the Professional Builder Top Product Award in both 2024 and 2025.

Flat roof skylights in the UK start from £165 ex VAT for a 500x500mm frameless unit. Framed rooflights start from £392 ex VAT. Prices increase with size and glazing specification. Custom sizes are available with delivery within 7 to 10 working days.

Velux is a brand name primarily associated with pitched roof windows, though they produce products for flat roofs too. A flat rooflight is a product category, covering glazed units designed to be installed within or just above a flat roof surface. UK manufacturers produce flat rooflights across a wider range of sizes, finishes and glazing specifications than Velux's standard flat roof range.

In most cases, yes. Provided the roof opening dimensions are compatible and the upstand is correctly prepared for the replacement unit, a UK flat rooflight can be installed in place of a Velux product. Our team can advise on sizing and specification with your opening dimensions before any order is placed.

A quality flat roof skylight installed correctly should last 20 years or more with basic maintenance. UK-manufactured rooflights from Rooflights and Skylights UK carry a 10-year guarantee as standard, reflecting the confidence behind the materials and manufacturing process behind every unit.

For most residential installations, double glazed clear Low-E glass delivers the right balance of light transmission and thermal performance. Triple glazing is the appropriate specification for high-energy-efficiency projects or north-facing installations where heat retention is the priority. Solar control glass is recommended for south-facing rooflights to manage summer heat gain and prevent overheating.