

Flat Roof Skylight 1200 x 2500 mm, Fixed, Frameless, Triple Glazed,161.70kg, UV 0.9
£ 1.970.00 Original price was: £ 1.970.00.£ 1.410.00Current price is: £ 1.410.00. incl. VAT
Prices go up when the timer hits zero.
17 in stock (can be backordered)
Skylights.co.uk: Trusted rooflights. Built to prevent leaks.
Type: Fixed Frameless Flat Roof Skylight
Internal Size: 1200 x 2500 mm
External Size: 1400 x 2700 mm
Glazing Type: Triple Glazed
Net Weight: 161.70kg
U Value: 0.9 W/m²K
G Value: 58%
Light transmittance : τv [%] 72
Sound reduction (EN 12758): 39dB
UV transmission : τuv [%] 0
Toughened safety & laminated glass
Leakproof Design
Our Flat Roof Skylights are composed of three distinct glass panes, each contributing to the unit’s durability and thermal efficiency:
- Top Pane: 8 mm Planibel Clearlite / Thermally toughened glass BS EN 12150
- Middle Pane: 6 mm Planibel Clearlite / Thermally toughened glass BS EN 12150
- Bottom Pane: 6 mm iplus Thermally toughened glass with Low-E coating EN 12150
Premium Flat Roof Skylights
Thinking about installing a skylight but worried about heat loss? Our Flat Roof Skylight measuring 1200 x 2500 mm boasts an outstanding U-value of 0.9 W/m²K, thanks to its triple-glazed units and warm edge spacer technology. This ensures excellent insulation, keeping your space warm in winter and cool in summer while allowing in abundant natural light.
Why Choose Our Frameless Flat Roof Windows
- Energy Efficiency: Benefit from superior thermal performance with our triple-glazed units and warm edge spacer technology, resulting in a U-value of 0.9 W/m²K for consistent comfort and reduced energy expenses.
- Unobstructed Views: The frameless design maximizes natural light penetration and offers stunning panoramic sky views.
- Self-Cleaning Feature: Enjoy easy maintenance with a sunlight-activated self-cleaning feature that keeps your glass sparkling clean.
- Versatile Installation: Ideal for flat roofs with pitches between 6° and 45°, fitting various home styles.
- Quiet Ambiance: Effective soundproofing ensures a peaceful indoor environment.
- UV Protection: Safeguards your interior from harmful UV rays.
- Safety First: Constructed with safety-toughened glass for enhanced security.
- Regulation Compliant: Fully compliant with British Standards & Building Regulations and carries the CE safety marking.
Essential Skylight Accessories
Upgrade your flat roof skylight setup with essential accessories for smooth roof window installation and optimal performance:
- Skylight Blinds for Flat Roof Window 1200x2500mm: Custom-fit blinds provide light control and privacy, tailored specifically for your skylight size.
- Installation Kit for 1 x Flat Roof Skylight 1200x2500mm: A comprehensive kit for secure, hassle-free installation, ensuring optimal performance and durability.
- Foam Rope – Structural Glazing Tape – 9mm Thick (7.5m Rolls): Offers effective sealing and structural support during installation.
- Weatherproofing Sealant (Silicon) – DOWSIL™ 791, 310ml: Creates a durable, weatherproof seal around your skylight, keeping the elements out.
- Self-Cleaning Liquid Smart Glass Bottle 15ml: Replenishes the self-cleaning properties of your skylight, ensuring easy maintenance and spotless glass.
Choose Skylights.co.uk
We offer an extensive range of standard sizes, including the popular 2500 x 1200 mm skylight (also known as 2.5 x 1.2 m roof light), as well as fully custom skylights tailored to your specific requirements. Our flat rooflights deliver:
- Exceptional Thermal Performance: Triple glazing ensures superior insulation and year-round comfort.
- Natural Light Abundance: Our skylights flood your space with beautiful natural light, creating a bright and inviting atmosphere.
- Elegant Design: Sleek, modern designs that add a touch of sophistication to any setting.
Download our full product catalogue to explore our extensive range of flat roof skylights and find the perfect solution for your project.
Ready to discuss your skylight needs? Contact us today!
🗺️ Where to Buy 1200 x 2500 mm Roof Lights Near Me
Looking to buy a 1200 x 2500 mm roof light near you? Also known as a 1.2 x 2.5 m large skylight, this size brings show-stopping daylight to larger zones like open-plan kitchens or vaulted ceilings. We manufacture frameless flat rooflights that combine visual elegance with structural performance.
✅ Bespoke Large Skylight – Designed for Impact
✅ Triple Glazed – Excellent Thermal Control
✅ Built for UK Weather – Condensation-Free Design
✅ Fast UK Delivery from Our In-House Factory
✅ 20-Year Guarantee – No Hidden Terms
Every unit is UKCA-certified and built with the confidence professionals rely on. Order online and let the light do the talking.
Weight | 108 kg |
---|---|
Dimensions | 205 × 10 × 145 cm |
Brand |
Skylights.co.uk |
Internal Size |
1200 x 2500 mm |
External Size |
1400 x 2700 mm |
Glazing Type | |
Glass Tint | |
Self-Cleaning: |
Yes |
Roof Type |
Flat Roof ,Pitched Roof |
Skylight Type |
Frameless |
Top Glass Pane: |
8 mm Planibel Clearlite / Thermally toughened glass EN 12150 |
Air Gap |
16 mm Argon 90% |
Middle Glass Pane: |
6 mm Planibel Clearlite / Thermally toughened glass EN 12150 |
Air Gap |
16 mm Argon 90% |
Bottom Glass Pane: |
6 mm iplus 1.1 pos.5 Thermally toughened glass with Low-E coating EN 12150 |
Spacer Type |
15mm Black Warm Edge |
U value |
0.9 [W/(m².K)] |
Sound reduction - EN 12758 |
[dB] 39 (-2;-7) |
Light transmittance: tv [%] |
72 |
External light refection : ρv [%] |
17 |
Internal light refection : ρvi [%] |
17 |
Colour rendering index : Ra [%] |
97 |
Solar energy transmittance : g [%] |
57 |
Shading coefcient : SC |
0.66 |
Selectivity |
1.26 |
UV transmission : τuv [%] |
0 |
Sold By Manufacturer
17 in stock (can be backordered)
11 in stock (can be backordered)
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Transform your home with our triple-glazed flat roof skylights, maximizing natural light and thermal efficiency. Pair them with our separately sold Insulated Upstand, featuring 40mm core insulation to cut heat loss and lower energy costs.
Why Choose Our Insulated OSB Upstands?




Perfect Pitch for Water Drainage
Built-In 6° Pitch for perfect drainage

Exceptional Insulation
High Insulation with 40mm core and 15mm OSB

Ready-to-Install, Precision-Cut Fit
Factory-made to match our skylights exactly
Brighten Your Home & Save More – Bundle & Save!
Upgrade with our triple-glazed flat roof skylights for maximum light and energy efficiency.
Add the Insulated Upstand and save up to 7% with our bundle offer!
✔️ Boost thermal performance
✔️ Cut energy costs
✔️ Enjoy lasting durability
Get the complete solution at a better price – bundle today!
Get a Bundle with extra 7% Discount on Skylight and Upstand
Flat Roof Skylight 1200 x 2500 mm, Fixed, Frameless, Triple Glazed,161.70kg, UV 0.9
Inclined Insulated Upstand for Flat Roof Skylight 1200 x 2500 mm


Before and After
See how a space is completely transformed with a Skylights.co.uk.
- Maximum daylight
- Modern minimalist design
- Superior insulation & UV protection
One change. Total transformation.
Our Roof Windows in Action
Photos from completed projects by our clients









Quick Shipping
Get it fast with our expedited shipping options.

Secure Payment
Shop safely with our secure online checkout.

Easy Returns
Hassle-free returns within 30 days.

20 Year Warranty
Enjoy peace of mind with our extensive warranty.

TILE & MEMBRANE COMPATIBLE
FLAT ROOFS
EASY & SECURE INSTALLATION
Will It Fit My Roof?
1. Flat Roofs
Our skylights are suitable for flat roofs with a minimum pitch of 6° when installed with the correct upstand or flashing kit.
2. Tile & Membrane Compatible
Designed for all common UK roof types – from clay tiles and slate to EPDM, GRP, and bitumen flat roof membranes.
3. Easy & Secure Installation
Each skylight is engineered for watertight, airtight installation. Use our installation kits and add our pre-fabricated upstands for a perfect fit and finish.
FAQ
Our triple-glazed models offer U-values as low as 0.9 W/m²K (whole unit), helping you meet Part L regulations and reduce heat loss.
Yes. All our skylights come with self-cleaning glass as standard to reduce dirt buildup.
Yes. We offer made-to-measure rooflights to fit your exact requirements. Contact us for a custom quote.
Yes. When installed with our official flashing kit and according to instructions, it is guaranteed to be watertight.
Absolutely. Each unit uses toughened outer and laminated inner glass that complies with UK safety standards (EN12150 / EN14449).
We offer a 20-year guarantee on the glazing unit.
Ella Reynolds –
Adding a skylight to our staircase area was a brilliant move. The difference in light and ambiance is astounding.
Charlotte Evans –
Adding a skylight to our dining room has truly elevated the entire ambiance of our home. The KingsView team here in Newcastle was exceptional, guiding us through every step with professionalism. The light it adds is just breathtaking.