Everbuild Fire Sealant 300 Intumescent Sealant – Box 25

Everbuild Fire Sealant 300 is an intumescent and acoustic acrylic sealant designed for sealing penetrations, joints and voids in fire-rated structures. When temperatures exceed 150°C, it expands to seal the opening and prevent fire and smoke from passing through. It carries a fire rating of up to 5 hours, tested to BS 476 Part 20 and EN1366-4 (2006), which is the kind of certification that actually matters when a building inspector turns up.

It’s an acrylic-based formula, so it’s easy to apply from a standard cartridge gun, cleans up with water before it cures, and can be painted over once dry. That combination of compliance and ease of use is why it’s a go-to choice for passive fire protection work on commercial and residential sites alike.

Beyond fire performance, Fire Sealant 300 also carries an acoustic rating to BS EN ISO 140/3, making it useful in situations where sound attenuation is required alongside fire separation. It has also been tested for air permeability to EN13141-1, relevant for buildings where controlled ventilation is part of the design.

Where Everbuild Fire Sealant 300 Gets Used

The typical application is sealing around pipes, cables and other services that penetrate fire walls or compartment floors. Any time you push a conduit through a fire-rated partition, that hole needs filling with a compliant sealant. Fire Sealant 300 handles irregular shapes and gaps well, making it practical for the kind of messy penetrations you find on real sites rather than in product brochures.

Frame Sealing and Acoustic Applications

It’s also specified for the internal perimeter pointing of fire-rated door and window frames, where maintaining the integrity of the fire barrier at the frame joint is a requirement. The acoustic rating adds value in situations where the same seal needs to reduce sound transmission between compartments, such as in flats, hotels and office fit-outs. Available in grey and white to suit different substrate finishes.