VELUX CFU & ISU Fixed Curved Glass Flat Roof Window

VELUX Fixed ISU Curved Glass Flat Roof Window with CFU Base

Stylish, Maintenance-Free Roof Window for Flat Roofs (0–15° Pitch)

The VELUX Fixed Curved Glass Rooflight (ISU Top + CFU Base) is a sleek and durable fixed roof window, ideal for adding natural light to flat roof spaces. Its modern, curved glass design not only looks stunning but is also practical — allowing rainwater to run off naturally, even at pitches as low as 0°.

Key Features:

For Flat Roofs (0–15° Pitch): Perfect for extensions, bathrooms, hallways, and more

Two-Part Design: Includes CFU fixed base unit + ISU curved glass top

Curved Glass Top: Frameless design for rainwater runoff and a modern finish

Double or Triple Glazing: Choose the performance you need

Low Maintenance: Self-cleaning curved glass with UV protection

Multiple Sizes Available: Fits small rooms to large open-plan areas

10-Year Warranty: Long-lasting VELUX quality assurance

Product Benefits:

Uninterrupted Natural Light: Frameless curved glass edge brings in more daylight

No Standing Water: Curved design helps water drain away, even on flat roofs

Energy Efficient: Choose double or triple glazing for excellent insulation

Safe & Secure: Laminated inner pane for added safety

Architectural Appeal: A stylish upgrade from traditional domes or flat rooflights

Technical Performance

Feature	Double Glazing (ISD)	Triple Glazing (IST)
Thermal Insulation (Uw)	1.2 W/m²K	0.95 W/m²K
Noise Reduction	36 dB	42 dB
Glass Composition	Outer toughened, inner laminated	Outer toughened, inner laminated
Solar Heat Gain (g-value)	0.52	0.37
Light Transmission	~69%	~63%
Reaction to Fire (EN 13501-)	Broof (t1)	Broof (t1)

 

What’s Included:

CFU Fixed Base Unit

ISU Curved Glass Top Unit

Installation instructions

 

 Available Sizes:

A wide range of standard sizes is available. Select your size from the drop-down menu above to suit your space.

Perfect For:

Flat roof home extensions

Kitchens, bathrooms, and stairwells

Contemporary residential and commercial designs

Projects needing a modern, low-maintenance rooflight

 

Bring light and style to your flat roof project with the VELUX Fixed ISU Curved Glass Rooflight – order now with fast delivery and full warranty support.