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Everflex Fire-Fill: Interior Fire Rated Joint Sealant (AS1530.4 Certified)
Everflex Fire-Fill is a water-based, intumescent acrylic sealant engineered to provide certified fire resistance in linear joints within interior construction. Designed for use in wall and floor junctions, control joints, and penetrations, Fire-Fill expands when exposed to heat — helping to block fire, smoke, and toxic gases. It cures to a flexible, paintable finish and delivers up to 4 hours fire protection when used in approved configurations. Suitable for use in fire-rated walls, concrete slabs, precast panels, partition junctions, and service penetrations. Ideal for passive fire protection systems in residential, commercial, healthcare, and institutional buildings.
Key Technical Features
- Up to 4 hours fire rating – tested to AS1530.4 for compliance with NCC passive fire safety
- Intumescent formula – expands under heat to seal gaps and block fire spread
- Low shrinkage acrylic – maintains joint integrity as it dries
- VOC compliant & low odour – suitable for use in enclosed or sensitive environments
- Paintable surface – allows seamless finishing with most architectural coatings
- Primerless adhesion – bonds directly to porous surfaces like concrete, block, plasterboard
- Non-hazardous & easy to clean – water-based formula is safe and installer-friendly
Where to Use Everflex Fire-Fill
- Linear control joints in fire-rated walls and floors
- Junctions between plasterboard and concrete slabs
- Slab-to-wall interfaces in multi-storey buildings
- Around fire doors and service penetrations in compliant systems
- Internal blockwork and precast panel joints
Why Choose Fire-Fill?
- Proven fire protection for passive compliance — up to 4 hours rating
- Spec-compliant with NCC and AS1530.4 tested systems
- Cleaner and faster to apply than fire mastics or mortars
- Ideal for dry internal applications — hospitals, schools, apartments, commercial fitouts
- Trusted by Australian builders and certified to support fire engineering requirements
Frequently Asked Questions
What fire rating does Everflex Fire-Fill achieve?
When used in compliant joint configurations, Everflex Fire-Fill can achieve up to 4 hours fire resistance as tested in accordance with AS1530.4. Fire rating results depend on joint size, backing material, and substrate type.
Is Fire-Fill suitable for external or wet areas?
No — Fire-Fill is designed for internal use only. It is not waterproof and should not be used in areas exposed to weather, high humidity, or permanent moisture. For external fire-rated sealing, use a polyurethane or hybrid fire-rated sealant.
Can I paint over Everflex Fire-Fill?
Yes. Once fully cured, Fire-Fill can be painted with most water-based paints. Ensure full drying before overcoating to avoid cracking or adhesion issues.
Do I need a primer before applying Fire-Fill?
In most cases, no primer is required. Fire-Fill adheres well to porous substrates such as concrete, brick, block, and plasterboard. On very dusty or coated surfaces, testing is recommended.
Is Everflex Fire-Fill tested to Australian standards?
Yes — Fire-Fill is tested to AS1530.4, the Australian Standard for fire resistance of elements of construction. Always refer to the test report or compliance certificate for installation-specific guidance.
Applications & Benefits
| Application / Use Case | Key Benefit | Primary Trades |
|---|---|---|
| Fire-rated wall/floor junctions in concrete slabs | Intumescent seal limits flame and smoke transfer for up to 4 hours | Builders, Passive Fire Installers |
| Control joints in plasterboard walls and partitions | Maintains flexible fire-rated barrier between adjoining systems | Plasterers, Fitout Contractors |
| Seal around fire-rated doors and steel frames | Forms a compliant smoke/fire seal with paintable finish | Fire Door Installers, Carpenters |
| Slab edge joints between blockwork and concrete | Primerless adhesion with reliable fire containment at interfaces | Blocklayers, Structural Contractors |
| Passive fire sealing around pipe or cable penetrations (in systems) | Compatible with tested systems for penetration protection | Fire Safety Contractors, M&E Trades |
How to Apply Everflex Fire-Fill
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1. Prepare the Surface
Ensure all joint surfaces are clean, dry, and dust-free. Remove loose debris, laitance, or release agents. Light abrasion is recommended for glossy painted surfaces. Do not apply over damp or frozen substrates. -
2. Install Backing Rod
For deep joints, insert an appropriate backer rod to control sealant depth and avoid three-sided adhesion. Use open cell or closed cell rod sized to allow 25% compression. -
3. Apply Fire-Fill
Cut nozzle to suit joint width and apply using a standard caulking gun. Apply in a continuous bead, ensuring full contact with both sides of the joint. Do not apply in temperatures below 5°C or above 40°C. -
4. Tool & Finish
Tool the sealant within 5 minutes using a wet spatula or gloved finger to create a smooth finish. Clean excess with a damp cloth. Avoid tooling after skin formation begins. -
5. Curing & Painting
Allow a minimum 48-hour curing time before applying water-based paints. Cure time depends on temperature, humidity, and joint size. Protect from moisture during initial cure.
Limitations & Safety
Product Limitations
- Interior use only: Not suitable for external joints or exposed weather conditions.
- Not waterproof: Do not use in wet areas or where water exposure is likely.
- Non-loadbearing: Not suitable for trafficable expansion joints in floors.
- Do not use in submerged conditions: This is not a wet-area or immersion-grade sealant.
- Not for plastic surfaces: Poor adhesion to PVC, acrylic, or polycarbonate substrates.
- Temperature-sensitive: Application range is 5°C to 40°C. Protect from freezing during storage.
Safe Handling & PPE
- Wear gloves to avoid prolonged skin contact. Wash hands after use.
- Use in well-ventilated areas. Product is low-VOC but avoid inhaling vapours.
- Avoid contact with eyes. Rinse immediately with water if exposed.
- Product is non-flammable. Store in original containers away from heat sources.
- Refer to SDS for full first aid and toxicological details.
Adhesion & Surface Compatibility
✅ Excellent Adhesion – No Primer Required
- Concrete (precast or in-situ)
- Blockwork (core filled or solid)
- Plasterboard (paper-faced)
- Fibre cement sheet
- Brick (raw or uncoated)
- Painted or sealed porous masonry (after light abrasion)
Fire-Fill is designed for porous, dry, internal construction materials. It bonds well to mineral-based surfaces without the use of primer under typical site conditions.
⚠️ Surface Testing Recommended
- Painted steel door frames (gloss or powder-coated)
- Galvanised metal or flashings
- Fire-rated doors with factory coatings
- Timber reveals (sealed or painted)
Where painted or non-porous finishes are present, carry out adhesion testing or light surface abrasion prior to application. Do not apply over flaking or chalking paint.
❌ Not Suitable
- Exterior masonry or exposed joints
- Wet areas or areas subject to immersion
- Plastic surfaces (PVC, acrylic, polycarbonate)
- Aluminium composite panels
Fire-Fill is intended for interior dry conditions only. For waterproof or external applications requiring fire rating, consult Adheseal for suitable alternatives.
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