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Everflex JS High Performance Joint Sealer: A Technical Overview
Everflex JS is a professional-grade, low modulus hybrid acrylic sealant formulated to handle dynamic joint movement in Australia's varied climate conditions. With up to ±50% movement capability, it’s ideal for high-flex zones in commercial and residential construction. The sealant delivers consistent elasticity from -18°C to 80°C, maintaining strong adhesion without the need for primers on most common substrates. Its non-sag formula allows clean vertical and overhead application, while its ultra-high elongation (1000%) accommodates structural shifts without cracking or loss of bond. Everflex JS is non-toxic, isocyanate-free, and meets ASTM C-834 and TT-S-00230C Class A standards.
1000%
Elongation at Break – extreme flexibility for high-movement joints
Core Features & Specifications
- ±50% movement capability – handles dynamic joint expansion and contraction
- 1000% elongation – resists tearing under high-flex conditions
- Low modulus formula – ideal for applications where stress reduction is critical
- Non-sagging – perfect for vertical and overhead joints
- Primerless adhesion – bonds strongly to timber, concrete, metal, acrylic, polycarbonate and more
- Excellent UV resistance – suitable for long-term external exposure
- Paintable and low VOC – complies with Californian South Coast Rule 1168 (32g/L VOC)
- Service temperature range – maintains flexibility from -18°C to 80°C
The Everflex JS Advantage
- Delivers peace of mind in movement-prone joints with long-term elastic performance
- Reduces installation time with no need for primers on most substrates
- Supports fire-rated systems when paired with FireFoam backer rod
- Non-toxic and safe for indoor use, ideal for public spaces and sensitive environments
- Backed by Adheseal’s quality manufacturing and technical support across QLD
Best Practices: Do's & Don'ts
Do
- Use Adhefoam backer rod or bond breaker tape before sealant application
- Tool off immediately with a spatula to a flat finish
- Allow minimum 6mm and max 10mm depth in joints
Don't
- Apply if rain is expected within 90 minutes
- Use where water-absorbing backer rod may soak through
- Apply in joints deeper than a 2:1 width-to-depth ratio
Applications in Practice: Trade Scenarios
For Builders (On-site Applicator): Tilt-up Panel Joints
The Engineering Challenge
Tilt panels shift significantly due to thermal expansion and substrate settling. Inadequate sealants can crack, causing water ingress or joint failure.
The System-Based Solution with Everflex JS
Use Everflex JS with a 6–10mm sealant depth and Adhefoam backer rod. Its ±50% movement capacity ensures ongoing flexibility without cracking. Tool to flat finish for watertight seal.
Best Practice Note
Avoid installing before rainfall. Where horizontal joints may be exposed to pooling, top cap the joint to prevent rain-soaked backer rod issues.
For Glaziers (Remedial Specialist): Acrylic or Polycarbonate Glazing Joints
The Engineering Challenge
Many sealants stain or fail to bond properly with polycarbonate sheets, especially in exterior sunlit areas where UV exposure is extreme.
The System-Based Solution with Everflex JS
Everflex JS bonds well to acrylic and polycarbonate without primer. Its UV stability prevents yellowing and cracking around joints, even in exposed conditions.
Best Practice Note
Clean surfaces with isopropyl alcohol and ensure no static charge remains prior to application. Always test on plastics if sheet type is unknown.
Performance Benchmark: Everflex JS vs. Standard Alternatives
| Metric | Everflex JS | Standard Acrylic Sealant | Advantage |
|---|---|---|---|
| Elongation | 1000% Extreme Flexibility | 250–300% | Greater resilience for dynamic joints |
| Movement Capability | ±50% Best-in-Class | ±20% to ±25% | Handles more joint stress |
| VOC Content | 32g/L Low Emissions | 100–250g/L | Better for indoor air quality |
Frequently Asked Questions
How much joint movement can Everflex JS accommodate?
Everflex JS offers ±50% movement capability, making it ideal for joints exposed to structural shifting, expansion, and contraction. This flexibility is critical in tilt-up panel construction, windows, and façade joints where wide movement occurs due to temperature or settlement.
Can Everflex JS be applied without a primer?
Yes, Everflex JS is designed to bond directly to most common substrates including concrete, timber, metal, and plastics without a primer. For unusual or porous surfaces, adhesion testing is recommended before large-scale use.
Is Everflex JS suitable for use on polycarbonate or acrylic panels?
Yes. Everflex JS exhibits excellent adhesion to acrylic and polycarbonate without staining or yellowing. It is ideal for glazing applications where UV resistance and flexibility are required. Surface should be clean and free from static prior to application.
What is the recommended joint design when using Everflex JS?
Joints should be designed with a minimum depth of 6mm and a maximum of 10mm, with no more than a 2:1 width-to-depth ratio. Use Adhefoam backer rod or bond breaker tape to control depth and prevent three-sided adhesion.
Can Everflex JS be used for fire-rated joints?
Yes, fire rating can be achieved when Everflex JS is used in conjunction with FireFoam backer rod, as specified in the fire system design. Always refer to the relevant FireFoam data sheet for compliance parameters.
What should I do if rain is expected after applying Everflex JS?
Avoid application if rain is expected within 90 minutes of installation. As Everflex JS is water-based, it must skin over to prevent washout. Ensure the joint is protected or schedule works during dry weather windows.
Applications & Benefits
| Application / Use Case | Key Benefit | Primary Trades |
|---|---|---|
| Sealing joints in tilt-up or precast concrete panels | ±50% movement capability prevents cracking and ensures long-term durability | Builders, Concrete Contractors |
| Window and door perimeter sealing | Flexible and paintable for a seamless, professional finish | Glaziers, Carpenters, Joiners |
| Sealing expansion joints in brickwork and blockwork | Excellent weathering resistance with no primer required | Masons, Builders |
| Plastic glazing panels (acrylic/polycarbonate) | Non-staining adhesion to plastics with UV resistance | Glaziers, Facade Installers |
| Fire-rated construction joints (with FireFoam backing) | Compliant with fire rating systems using compatible accessories | Builders, Fire Compliance Installers |
Applying Everflex JS: Enhanced Protocols & Best Practices
-
Surface Preparation
All substrates must be clean, sound, dry, and free from dust, oil, or loose material. Remove laitance, grease, and any release agents from concrete or precast panels.
Method A: Dry Brushing & Solvent Wipe
Use a stiff brush to remove dust and debris, then wipe with isopropyl alcohol for metal, plastic, or smooth substrates.
Method B: Light Abrasion (where required)
For painted timber, galvanised metal, or aged surfaces, lightly abrade with fine sandpaper to improve adhesion.
Timing: Complete prep immediately prior to sealant installation to avoid contamination.Pro Tip: Test adhesion on suspect or aged surfaces before full application, especially on painted or coated substrates. -
Joint Backing Installation
Insert backer rod or apply bond breaker tape to control sealant depth and prevent three-sided adhesion. Select rod size to allow compression and ensure a snug fit within the joint.
Open Cell Backer Rod
Ideal for interior or protected joints. Compress slightly and insert to recommended depth.
Closed Cell Backer Rod
Use for exterior or high-moisture zones. Avoid piercing the outer skin, which can cause sealant gassing.
Timing: Install rod prior to sealant opening, and ensure it's fully dry before proceeding.Pro Tip: For fire-rated joints, use FireFoam backer rod as per fire compliance specifications. -
Sealant Application
Cut nozzle to match joint width and apply Everflex JS using a caulking gun. Apply in a continuous motion to avoid air entrapment.
Standard Caulking Gun
Use for standard control joints and edge sealing tasks. Maintain steady pressure for consistent bead.
High-Ratio Gun
Use on wider joints or thicker applications to maintain flow rate without fatigue.
Timing: Tool off immediately after application, within 5 minutes, before skin forms.Pro Tip: Tool to a flat finish, not concave. Do not wait to smooth the surface — apply and tool in one pass for best appearance. -
Curing & Weather Protection
Protect sealed joints from rain or water exposure for a minimum of 90 minutes to allow proper skin formation. Full cure time may vary depending on temperature and humidity.
Weather Shielding
Use plastic film or rain hoods over exposed joints if rain is likely within 2 hours of application.
Interior Joints
Ensure adequate ventilation to promote evaporation and curing. Avoid high humidity environments.
Timing: Do not expose to rain or washdown for 90 minutes post-application.Pro Tip: In humid or shaded areas, allow extended cure time before painting over.
Limitations & Safety
Product Limitations
Do not apply Everflex JS if rain is expected within 90 minutes, as it is water-based and may wash out before skin forms.
Avoid using in joints deeper than 10mm or with a width-to-depth ratio exceeding 2:1. Excess depth may result in sagging.
Do not allow backer rod to absorb water prior to curing, as this may cause sealant failure.
Everflex JS is not suitable for permanent water immersion or constantly submerged joints. Use alternative waterproof-grade sealants for those conditions.
Consider: Adheseal PU15 or Sil-X WP
Do not apply over poorly bonded paint, loose coatings, or dust-contaminated surfaces without proper surface prep.
Safety & Handling Requirements
Personal Protective Equipment
Wear protective gloves (nitrile or neoprene), safety glasses, and long sleeves during application. Product is non-toxic and non-hazardous, but may cause skin irritation in sensitive users.
Ventilation Requirements
Ensure adequate ventilation when working in enclosed areas. Although low-VOC (32g/L), air exchange will assist with faster curing and odour dissipation.
Fire & Handling Precautions
Product is rated as non-flammable. Store between 5°C and 32°C in sealed containers. Keep away from children and dispose of containers responsibly.
Emergency First Aid
Eyes:
Flush thoroughly with water for at least 15 minutes. Seek medical attention if irritation persists.
Skin:
Remove contaminated clothing. Wash skin with soap and water. Do not use solvents to clean skin.
Inhaled:
Remove to fresh air. If breathing is difficult, seek immediate medical attention.
Swallowed:
Rinse mouth. DO NOT induce vomiting. Seek urgent medical advice and show product label or SDS.
Seek medical attention immediately in all cases of serious exposure.
Everflex JS Application Guide
Concrete / Precast Panels
Surface Preparation
Clean surface thoroughly to remove dust, laitance, oil, or form release agents. Surface must be dry and sound prior to application.
Primer Requirements
No primer typically required
For high-performance or critical joints, adhesion testing is advised before large-scale use.
Adheseal PrimeSeal (optional for increased durability)Brickwork / Blockwork
Surface Preparation
Ensure joints are free of loose mortar, dust, and moisture. Allow mortar to fully cure before sealing.
No primer typically required
On dusty or porous surfaces, a light misting with water followed by drying can improve bond quality.
Timber (Painted or Bare)
Surface Preparation
Sand lightly to remove gloss from painted timber. Ensure bare timber is dry and free of dust or resin bleed.
Primer recommended for optimal adhesion
Test adhesion in a small area when sealing over painted or stained finishes.
PrimeSeal T or equivalentMetal (Aluminium, Galvanised Steel)
Surface Preparation
Degrease thoroughly with a solvent like isopropyl alcohol. Light abrasion may be required for painted or coated surfaces.
No primer typically required
Avoid using on rusted or heavily oxidised metals without surface prep.
Acrylic / Polycarbonate Sheets
Surface Preparation
Clean with a mild detergent solution and rinse well. Wipe with isopropyl alcohol to remove static and surface residues before applying sealant.
No primer typically required
Adhesion to these plastics is strong without primer, but compatibility testing is advised on unknown grades.
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