Everflex JS Hybrid Acrylic Sealant

For sealing interior and exterior expansion joints subject to movement, Everflex JS Hybrid Acrylic Sealant provides a low-modulus barrier that withstands weathering without cracking. This water-based joint sealer adheres to most building materials without priming and accommodates significant thermal and structural movement in both hot and cold climates.

What it does

Everflex JS Hybrid Acrylic Sealant fills moving joints across key construction substrates, including precast panels, blockwork, brickwork, and window frames. As a low-modulus sealant, it exerts low stress on the bond line, allowing the joint to expand and contract. Its hybrid acrylic formulation resists sagging in wide joints and tools to a smooth surface. The cured sealant is paintable, contains no isocyanates, and is non-staining.

Numbers that matter

• ±50% movement capability: Accommodates extensive joint movement under ASTM C-732 testing, exceeding standard building guidelines of ±25%.
• 6mm to 10mm joint depth: The required application thickness boundary regardless of joint width; do not exceed a 2:1 width-to-depth ratio.
• -18°C to 80°C service temperature: Maintains flexibility and bond integrity across extreme environmental service conditions.
• 32g/L VOC: Low-emission formulation meeting the Californian South Coast Air Quality Management Rule 1168.

Where to use it

Everflex JS Hybrid Acrylic Sealant is suitable for joints in the following areas and substrates:

• Precast panels and tilt-up construction
• Windows, doors, and general perimeter sealing
• Blockwork and brickwork
• Timber, metal, and plastics, including acrylic and polycarbonate

Limitations

• Do not apply if rain is expected within 90 minutes of application. Since this is a water-based sealant, rain will wash it out if a protective skin has not formed.
• Do not design or place joints deeper than a 2:1 ratio. The minimum depth is 6mm and the maximum depth is 10mm.
• On very wide joints, testing is required prior to application to ensure sagging does not occur.
• If using closed-cell backer rod, do not puncture or damage the outer skin, as this can release gas and cause bubbles to form in the curing sealant.

Installation

Ensure all joint surfaces are clean, sound, dry, and free of dirt, grease, laitance, and loose particles. For suspect surfaces, perform adhesion testing prior to full application.

Insert Adhefoam open-cell or closed-cell backer rod to control the sealant depth and prevent three-sided adhesion. Where the joint depth is too shallow for a backer rod, apply a bond-breaker tape. Tool the sealant immediately after application with a spatula to a flat, non-concave finish.

For joints requiring a fire rating, use Fire-Foam backer rod in accordance with its specific technical data sheet.