Flat roof window type F

Flat roof window type F

A minimalist and perfect designed DEF flat roof window has been awarded with prestigious Red Dot Design Award.

DEF Red Dot1


The innovative flat roof window D_F ColourLine allows you to match the colour of the window finish with the existing roof design. A wide range of colours in accordance with the RAL Classic Palette.

DEF Colour Line RAL

Flat roof window type F


The F-type flat roof window has a sleek, modern appearance, characterized by excellent thermal insulation parameters. The frame structure is the same as flat roof dome windows, however the main difference lies in the glazing unit which is joined using modern manufacturing technologies to produce a highly aesthetic and innovative design.


The F type is equipped with an energy-efficient, triple glazing unit DU6. The 6 mm thick outer glass is toughened, while the inner glass is laminated and anti-burglar class P2A. In the event of glass breakage, glass fragments do not pose a hazard but remain in the film sheet. The heat transfer coefficient for the whole window is U = 0,70 W/m2K (up to EN 14351-1). The window is also available to order with a quadruple glazing unit U8. The heat transfer coefficient for the entire D_F DU8 window is U = 0.64 W/m2K (up to EN 14351-1). Its excellent specifications make this window suitable for use in energy-efficient and passive buildings.


The DEF flat roof window with DU6 double-chamber glazing unit has been tested for sound insulation during heavy rain. The result achieved, LIA = 36 [dB]* confirms the high level of resistance against sound penetration, therefore the window is ideal for places where peace and quiet is desired.

* in accordance with ISO 10140-1/A2:2014. The result also applies to the windows: DXF DU6, DMF DU6, DXF SECURE (PK) DU6, DMF SECURE (PK) DU6, DRF DU6


The structure of the window allows the installation of internal as well as external accessories. The external awning protects against overheating of the room, while the internal accessories protect against bright sunlight and provide decorative elements.


The type F flat roof window is suitable for roof pitches between 2 and 15 degrees.


The wide range of sizes available correspond to standard skylights, allowing for quick and easy replacement of an existing skylight for a new window.

*A minimalist and perfectly designed DEF flat-roof window, awarded with Red Dot Design.


The innovative D_F ColourLine flat-roof window allows you to match the colour of the window finish to the existing roof design. Wide range of colours according to the RAL Classic Palette.