Skylights For Flat Roofs

Skylights for Flat Roofs

Flat roofs need a different kind of skylight to a pitched roof window. Instead of tilting into the slope, a flat roof skylight sits on a raised upstand and is built to shed water off a much shallower pitch, typically 0° to 15°.

Toughened Glass Systems supplies the full range: our own flat rooflight designs, Korniche and Coxdome flat glass units, Mardome polycarbonate domes, and roof lanterns from Korniche, Wendland and Brett Martin. Every product below links through to full specifications, sizing, and lead times.

New here? Read our Best Skylights for Flat Roofs: Complete Buying Guide first to work out which type suits your project. Already know what you want? Browse the range below.

10 Year Guarantee

Nationwide Delivery

Our own flat rooflight range

These are TGS’s own designs, manufactured to our own specification rather than a third-party brand.

Flat Rooflight £259.00 to £2,800.00 ex VAT. Our entry-level flat glass option, available double glazed (U-value 1.1) or triple glazed (U-value 0.9).
Triple-Glazed Self-Cleaning Rooflight £163.00 to £619.00 ex VAT. U-value 0.9, 20-year warranty, 1 to 3 working day lead time.
Framed Rooflight TGS £350.00 to £2,733.20 ex VAT. Double glazed (U-value 1.2) or triple glazed (U-value 0.7), PAS 24 security as standard, 2 to 5 working day lead time on the first ten sizes.
Framed Flat Skylights £420.28 to £3,558.06 ex VAT. Laminated inner glass pane rather than toughened-only, centre pane U-value of 1.1, 2 to 3 working day lead time on standard sizes.

Roof lanterns for flat roofs

A roof lantern sits above the roofline rather than flush with it, giving a pitched glass profile over a flat roof extension.

Korniche Roof Lantern £694.56 to £4,247.01 ex VAT. Slim sightlines, U-values from 1.0 to 1.2, self-cleaning glass as standard, 10-year warranty, 2 to 3 week lead time.
Wendland Roof Lantern £449.45 to £2,009.28 ex VAT. U-value 1.2 as standard or 1.0 as an upgrade, 10-year warranty, 5 to 10 working day lead time.
Brett Martin Roof Lantern £915.28 to £1,946.94 ex VAT. 10-year warranty, 3 to 5 working day lead time on the clear four-pane configuration, 10 to 15 working days on other specifications.

Opening rooflights for flat roofs

These units open manually with a winding pole or electrically via a wall switch, remote, or rain sensor, letting you add ventilation to a flat roof extension, kitchen, or bathroom. Available as flat glass or polycarbonate dome, and as a manual or electric upgrade on most of our opening rooflights range.

TGS Electric & Manual Opening Rooflights £618.81 to £9,999.00 ex VAT. Flat glass, centre pane U-value 1.1, manual with pole or mains powered with wall switch, remote, or remote and rain sensor, 10-year warranty, 3 to 5 working day lead time on the 9 standard sizes.
Coxdome Manual Glass Opening Rooflight £761.75 to £1,636.72 ex VAT. Flat glass, U-value 1.0, 35dB sound reduction, manual opening with an optional winding rod, 10-year warranty, 3 to 5 working day lead time.
Coxdome Lumiglaze Electric Opening Rooflight £1,173.12 to £3,183.65 ex VAT. Flat glass with a ceramic edge coating and internal thermal break, wall switch, remote, or wind and rain sensor operation, 10-year warranty, 3 to 5 working day lead time.
Mardome Electric Opening Polycarbonate Dome £480.27 to £2,924.30 ex VAT. Single, double, triple, or quad skin, wall switch, remote, or remote and rain sensor operation, 10-year warranty, 2 to 3 working day lead time on standard sizes.

Specialist flat roof rooflights

Walk-On Rooflights £869.00 to £3,575.00 ex VAT. Built for roof terraces and basement conversions, 15 to 23 working day lead time depending on location.
Circular Rooflights £977.13 to £3,230.39 ex VAT. Brett Martin Circular Glass in four fixed diameters (600mm to 1500mm), 10-year warranty, 15 to 30 working day lead time.
Modular Rooflights £2,348.98 to £15,589.91 ex VAT. Mardome Glass Link modules for large commercial spans, 4 to 6 week lead time.

Frequently asked questions

What branded flat glass rooflights do you sell?

Korniche Flat Lite £109.50 to £875.10 ex VAT. PAS 24 high security glazing, 10-year manufacturer’s warranty, 2 to 3 week lead time.
Coxdome Flat Glass Rooflight £577.30 to £1,484.65 ex VAT. U-value 1.0, 35dB sound insulation, 3 to 5 working day lead time.

What dome and polycarbonate rooflights do you sell?

Dome rooflights are a lower-cost alternative to flat glass, often used on extensions, garages, and commercial roofs.

Mardome Trade Polycarbonate Dome £115.00 to £1,853.17 ex VAT. Single, double, triple, or quad skin, 10-year warranty, 2 to 3 working day lead time on standard sizes.
Mardome Reflex Dome Only £123.63 to £1,145.28 ex VAT. Glazing-only unit designed for refurbishment projects replacing an existing dome, 10-year warranty, 2 to 3 working day lead time.
Coxdome Galaxy Dome Only £131.79 to £4,194.75 ex VAT. Also designed for refurbishment and glazing replacement, 10-year warranty, 2 to 3 working day lead time.
Coxdome Polycarbonate Dome £241.69 to £1,433.48 ex VAT. Double, triple, or quad skin with PVC-u upstand, 10-year warranty, 2 to 3 working day lead time.

Why buy skylights for flat roofs from Toughened Glass Systems?

Best Price Guarantee. We match like-for-like prices on equivalent products.
Named brands and our own range. Korniche, Mardome, Coxdome, Wendland and Brett Martin, alongside our own manufactured flat rooflight designs.
Fast UK-wide delivery, with lead times published on every product page so you know what to expect before you order.
Real technical specifications. U-values, warranty terms and lead times are stated per product, not blended across the range.

Learn more about skylights for flat roofs:

What's the difference between a flat roof skylight and a roof lantern?

A flat roof skylight sits flush on the upstand with a single flat pane. A roof lantern projects above the roofline with a pitched, multi-paned structure, giving a more architectural look but usually needing more structural support. See our flat vs pitched roof skylight extensions guide for a fuller comparison.

Do I need planning permission for a flat roof skylight?

Usually not. Most installations fall under permitted development in England and Wales, provided the unit doesn’t project more than 150mm above the roof plane. Listed buildings, conservation areas, and Article 4 directions are the main exceptions. Full detail in Can You Install a Rooflight on a Flat Roof?

What's the minimum roof pitch for a flat roof skylight?

Flat roof skylights are designed for pitches between 0° and 15°. Check the specific product page for its minimum pitch requirement before ordering.

How much does a flat roof skylight cost?

Prices on this page range from around £109 for a small fixed unit up to several thousand pounds for larger or modular systems. Installation is separate – see How Much Does it Cost to Install a Flat Rooflight? for a full breakdown.

Can I get an opening flat roof skylight?

Yes – most ranges on this page are available in fixed or opening configurations, with manual or electric operation. Browse our opening rooflights range, or read Electric vs Manual Opening Skylights to decide which suits your room.

Glass or polycarbonate – which should I choose?

Glass gives better optical clarity and won’t discolour over time. Polycarbonate domes cost less and offer strong impact resistance, making them a practical choice for garages, extensions, and commercial roofs. Browse dome rooflights or flat glass options above.

What warranty comes with these skylights?

Most products on this page carry a 10-year warranty, with a few extending further – full figures are listed against each product above. See How Long Do Rooflights Last? for what typically limits lifespan beyond the warranty term.

What lead time should I expect?

It varies by product rather than by price – standard-size dome rooflights typically ship in 2 to 3 working days, while made-to-order flat glass units and roof lanterns can take 2 to 3 weeks. Exact lead times are stated on each product listing above.

Can I install a flat roof skylight myself?

Standard-size units can often be fitted by a competent builder, provided the upstand is already correctly built. Roof lanterns and larger or modular systems are more likely to need structural input. Full process in Can You Install a Rooflight on a Flat Roof?

What U-value should I look for?

Lower is better for thermal performance. Triple-glazed options on this page reach as low as 0.9, while double-glazed domes sit higher. If you want a full walkthrough of what U-value means for your project, see our complete buying guide.

Do you sell anything other than flat rooflights and lanterns?

Yes – alongside the ranges above, we also stock pyramid skylights and fixed rooflights for flat roof applications. View our full range of rooflights, skylights, and roof windows.

How do I stop condensation on a flat roof skylight?

Condensation is usually a ventilation issue rather than a fault with the glass — an opening skylight helps by letting moist air escape. Read our guide to stopping condensation on rooflights for more.

Discover our full range of Flat Roof Windows