Cembrit put our Windstopper Extreme and Patina panels through a full CWCT sequence with UL in 2021 to test the full performance of the system.
 
Air Leakage (Infiltration & Exfiltration)  / CWCT Section 5
Water Penetration – Static  / CWCT Section 6
Water Penetration – Dynamic Aero Engine / CWCT Section 7
Water Penetration – Hose / CWCT Section 9
Wind Resistance – Serviceability / CWCT Section 11
Wind Resistance – Safety / CWCT Section 12
Impact – Retention to Performance & Safety to Persons / CWCT TN 76

Cembrit Windstopper Extreme has been tested in accordance to BS EN 1364-1:2015 (BS 476-22:1987). As part of a non-load bearing vertical building element Windstopper Extreme 9mm will provide up to 120 minutes of fire resistance when exposed to fire from one side.

Fire Resistance Test In Accordance With BS EN 1364-1:2015 Cembrit Windstopper Basic has been tested in accordance to BS EN 1364-1:2015 (BS 476-22:1987). As part of a non-load bearing vertical building element Windstopper Basic 9mm will provide up to 60/60 minutes of fire resistance when exposed to fire from one side.

Agrément Certificate Product Sheet relates to Windstopper Extreme, fibre-cement boards for use externally as sheathing boards to new and existing buildings, providing temporary weather protection prior to over-cladding with a permanent façade rainscreen cladding. The boards can be used structurally when applied to steel-frame substrate walls. The boards are non-structural when applied to timber-frame substrate walls, providing racking resistance where required.

SINTEF certify that Windstopper can be used as a wind barrier system and may stay exposed to external climate for up to 12 months before a cladding is installed on the outside. **When installed in conjunction with Cembrit Windstopper Tape.**

Agrément Certificate Product Sheet relates to Westerland Slates, acrylic-coated, fibre-reinforced cement slates for use on conventional pitched timber roofs with a rafter pitch of 20° and over, or hung vertically as cladding on external walls.

CERTIFICATION INCLUDES:
• factors relating to compliance with Building Regulations
where applicable
• factors relating to additional non-regulatory information
where applicable
• independently verified technical specification
• assessment criteria and technical investigations
• design considerations
• installation guidance
• regular surveillance of production
• formal three-yearly review.

Strength: the product has adequate strength to resist the loads associated with installation of a roof or an external wall cladding.
Properties in relation to fire: the use of the product as a roof or an external wall cladding is unrestricted under the national Building Regulations.
Weather resistance: the product will resist the passage of moisture into a building.
Durability: under normal  conditions, life in excess of 30 years.