Bostik Fireban One Polyurethane Sealant

For joints in insitu concrete, precast panels, blockwork, plasterboard, and fiber cement sheet requiring fire or acoustic certification, Bostik Fireban One Polyurethane Sealant provides up to a 4-hour fire rating under AS 1530.4-2014 and AS 4072.1-2005. This Australian-made, one-part intumescent sealant cures to form a tough, flexible barrier that accommodates continuous cyclic expansion and contraction in joints up to 50mm wide.

How it works

Fireban One Polyurethane Sealant is a low-modulus, thixotropic moisture-curing polyurethane. When exposed to fire, the intumescent formulation helps block the passage of flame and hot gases through construction joints. Its low-modulus characteristic limits stress on the bond line, allowing the cured sealant to absorb thermal expansion, wind loads, and structural settling. The non-sag paste consistency makes it suitable for vertical expansion joints in brickwork, masonry walls, and overhead panel connections. It does not support fungal growth under AS1157-1972 and remains stable under weather, rain, and UV exposure.

Numbers that matter

• ±25% joint movement: Absorbs cyclic contraction and expansion across precast tilt-up panels and concrete slab joints without adhesive or cohesive failure.
• 4-hour fire rating: Tested to AS 1530.4-2014 and AS 4072.1-2005 for fire-rated wall, floor, and linear joint systems.
• >900% elongation at break: High elasticity prevents the cured sealant bead from tearing during extreme structural shifting or joint widening.
• 2mm per 24 hours cure rate: Standard curing window on porous substrates, achieving tack-free status in 6 to 12 hours and full cure in 7 days.
• 0.5 to 6.0 lineal metres coverage: Yield per 600ml sausage ranges from 6.0 metres for a 10mm x 10mm joint down to 0.5 metres for a 25mm x 50mm joint.

Where to use it

Fireban One Polyurethane Sealant bonds to both porous and non-porous substrates, including:

• Insitu concrete floors and walls, precast and tilt-up panels
• Brickwork, blockwork, and rendered masonry
• Fire-rated and acoustic-rated plasterboard and fiber cement sheet
• UPVC penetrations, brass, copper, and stainless steel fittings and trays

Limitations

• Do not apply to cement-based substrates within 28 days of the initial concrete pour or pour set.
• Do not use in chlorinated water, such as swimming pools, spas, or in constant salt water immersion.
• Do not use on any materials containing bitumen.
• Do not use for glazing applications.
• Do not use in trafficable joints wider than 10mm.
• Do not apply at temperatures below 5°C or above 35°C.
• Do not expose the sealant to water or alcohol before it has cured.
• Do not use wet tooling techniques, such as soapy water, during installation.
• Do not apply in joints less than 6mm in width and depth.
• If painting, wait a minimum of 7 days. Coatings containing solvents (such as enamels or oil-based paints) may cause the sealant surface to become tacky, discolour, or crack under cyclic movement.

Preparation and priming

Clean and dry all surfaces to remove laitance, oil, dust, grease, curing agents, water, or old sealants. Vacuum loose dust from joints. Priming is recommended to achieve the stated performance properties. Do not use methylated spirits or turps to clean joints or prep surfaces.

• Porous substrates: Concrete or masonry structures not subject to water ponding or immersion do not require priming if they are clean and dry. For maximum performance or periodically immersed applications, use Bostik N49 Primer.
• Non-porous substrates: Prime plastics and metallic substrates (including UPVC, brass, copper, and stainless steel) with Bostik N40 Primer using the two-cloth method. Use Bostik Ultraseal for non-porous or burnished concrete.
• Joint Geometry: Install backing rod after priming to control sealant depth. Maintain a depth-to-width ratio of 1:1 for 10mm joints, and 1:2 for joints between 10mm and 50mm. Tool the sealant with a dry spatula to achieve a concave surface profile.