Everflex Fire-Fill Acrylic Sealant

For penetration pathways and expansion joints requiring a fire-resistant barrier, Everflex Fire-Fill Acrylic Sealant is tested in accordance with AS1530.4 and assessed to AS4072.1. This waterborne co-polymer-based intumescent sealant expands when exposed to fire, forming an inorganic plug that helps prevent fire transmission through partitions.

How it works

Everflex Fire-Fill functions by chemical expansion under heat. When exposed to fire, the intumescent material swells to block gaps around physical penetrations and linear joints. It accommodates up to ±20% joint movement while maintaining a flexible, waterproof joint. The formula is non-slump, water-cleanable while wet, and contains no isocyanates or asbestos. It has a low volatile organic compound content of 7g/L, meeting Green Star environmental criteria, and provides STC acoustic properties when installed in appropriate systems.

Numbers that matter

• AS1530.4 / AS4072.1: Tested and assessed fire standards achieving up to a 4-hour fire rating depending on the specific joint configuration and panel thickness.
• ±20% movement: Joint movement capability to absorb thermal and structural expansion without adhesive or cohesive failure.
• 50mm maximum width: Certified fire rating coverage for linear gaps up to 50mm wide.
• 2mm per 24 hours: Standard cure rate at 25°C and 50% humidity, with a tack-free skin time of 30 to 45 minutes.

Where to use it

This sealant adheres to most common construction substrates including concrete, aerated concrete (Hebel block), speed panel, masonry, brick, stone, plasterboard, timber, glass, aluminium, and plastics. It is suitable for:

• Expansion joints in precast and tilt-up panels.
• Linear gap seals in wall-to-wall and wall-to-floor configurations.
• Gap sealing around building services penetrations including cables, cable trays, metal pipes (except lead and copper), conduits, busways, and ducts.
• Double-sided and single-sided applications where wall integrity is adequate.

Limitations

• Do not use in trafficable or load-bearing joints.
• Do not use for sealing coated metal panels such as Colourbond.
• Do not apply to wet surfaces or when rain exposure is likely within 24 hours of application.
• Not suitable for long-term water immersion or internal swimming pool applications (avoid exposure to chlorine levels exceeding 5ppm).
• Do not use in totally confined spaces; the sealant requires atmospheric humidity to cure.
• Not suitable for aquariums, structural glazing, or adhering mirrors.
• Do not use on lead or copper.
• Stain testing is recommended prior to application on any natural stone.
• Do not expose the sealant to cleaning agents, solvents, or alcohol, particularly during the curing phase.
• Avoid application when moisture-vapour-transmission is emanating from the substrate, as trapped air may cause the sealant to bubble.

Installation and joint design

Joints should ideally maintain a 2:1 width-to-depth ratio. Internal joints require a minimum width and depth of 5mm; external joints require a minimum of 12mm. For joints deeper than 10mm, use an open-cell foam backer rod (such as Adhefoam) sized 25% larger than the joint width. Where space prevents a backer rod, apply a polyethylene bond-breaker tape to prevent three-sided adhesion.

Apply when substrate and air temperatures are between 5°C and 40°C (physical property application range is +5°C to +35°C). Fill the joint completely to avoid air entrapment. Tool dry with a moistened spatula within 5 to 10 minutes, before the surface skins. Masking tape should be removed immediately after tooling while the sealant is still wet.

New concrete must be allowed to cure for at least 28 days prior to application. While porous substrates do not normally require priming, optimal adhesion on highly stressed joints or under extreme weather exposure can be achieved by priming porous surfaces with Adheseal 2001 or Everflex Supaprime. For non-porous surfaces, slightly roughen the face and pre-treat with Adheseal 50A surface prep, allowing 30 minutes to 2 hours open time before applying the sealant.