25mm STEICO Fix - Wood-Fibre Insulation Wedge for Window Sills - 1350mm x 200mm - Pack of 10 - Pallet of 10

25mm STEICO Fix is a high-density, wedge-shaped insulation profile designed to sit directly beneath external window sills. Its primary function is to provide a thermally efficient, waterproof safety layer that directs any moisture or driving rain away from the structure and back to the outside of the building. In the UK’s driving rain, window sills are a common failure point. STEICOfix is specifically designed to solve this by creating a second water-bearing level.

Drip edge thickness: 8mm

CHARCTERISTICS

• The board is factory-cut into a wedge shape with a 5° tilt. This ensures that any water that manages to get past the primary window sill is immediately shed away from the timber frame or masonry.
• The top surface of the wedge is laminated with a high-performance, water-resistant membrane. This provides immediate protection against wind-driven rain and snow during the construction phase.
• With a rating of 200kPa, it is remarkably robust. It can easily support the weight of heavy window sills (stone, metal, or timber) without deforming.
• Like all Steico products, it significantly reduces "cold bridging" at the base of the window, which is traditionally a major source of heat loss.

APPLICATION

• New Timber Frame Builds: Provides a secure, second water-shedding layer under sills to protect the timber structure from rot.
• ETICS / External Render Systems: Installed as part of the STEICO Protect system to ensure window openings are fully weather-tight before rendering.
• Renovations: Ideal for upgrading older window openings to modern performance standards.

CERTIFICATIONS