Astro Intu Mastic – Trowel Grade is a water-based intumescent acrylic sealant designed to restore the fire resistance performance of wall and floor constructions where joints, gaps or service penetrations occur. Supplied in a workable paste consistency, it is applied using a trowel and is suitable for sealing larger openings and linear joints within passive fire protection systems.

When exposed to high temperatures, the sealant expands to help seal gaps around services and construction joints, maintaining compartmentation and helping to prevent the spread of fire and smoke. It is suitable for use with a wide range of penetrations including metallic pipes, cables, cable bundles, cable trays and cable ladders.

The product is suitable for use in flexible walls, rigid walls and rigid floor constructions and has been tested for both penetration sealing and linear joint applications. It is commonly used in conjunction with coated fire batt systems and can also be applied in blank openings, head-of-wall details and multi-service penetrations.

• Trowel-grade intumescent acrylic fire stopping sealant
• Designed to help reinstate fire resistance in wall and floor constructions
• Suitable for linear joints up to 50mm wide
• Tested for service penetrations including pipes, cables, trays and ladders
• Suitable for flexible walls, rigid walls and rigid floors
• Can be used with coated fire batt systems and blank openings
• Remains flexible and suitable for low movement joints
• CE marked and UKCA marked
• UL-EU listed
• Tested to EN 1366-3:2009 for penetration seals
• Tested to EN 1366-4:2009 for linear joints
• Classified in accordance with EN 13501-2
• Tested for airborne sound reduction to EN 10140-2
• Tested for air permeability to EN 1026

The sealant has a paste-like consistency with a matt finish, allowing controlled application into joints and openings using standard trowel techniques. Once cured, it forms a durable yet flexible seal capable of accommodating minor movement while maintaining the integrity of the fire stopping system.

Astro Intu Mastic – Trowel Grade is typically used as part of a tested passive fire protection system and should be installed in accordance with the relevant test evidence, certification and construction details for the wall or floor assembly involved.

Routine inspection and maintenance of installed fire stopping systems is recommended as part of the building’s fire safety management procedures. Any damaged or disturbed areas should be repaired promptly to ensure continued system performance.

Store unopened material in a cool, dry and well-ventilated environment and protect from direct sunlight. Normal safe handling and good site hygiene practices should be followed during installation and maintenance.