Sika SikaHyflex-305 AP

SikaHyflex 305 AP Features

SikaHyflex-305 AP is a one-component, neutral-cure, low-modulus silicone elastic sealant designed for curtain walls, metal-clad facades and demanding weather sealing applications requiring long-term durability. It offers excellent weathering and ageing performance with very high joint movement capability while maintaining good elasticity. The neutral-cure, solvent-free formula provides good adhesion to multiple substrates without causing corrosion or compatibility issues.

• One-component, neutral-cure silicone sealant
• Very high joint movement capability
• Excellent weathering resistance (highest rating)
• Very wide service temperature range
• Good adhesion to metals, glass, concrete and many substrates
• Neutral cure, solvent-free, no corrosion risk
• Good workability, easy to handle and control
• Compatible with other SikaHyflex and Sikasil silicone products

Applications

• Curtain Wall Joints — weather sealing joints in curtain wall systems
• Metal-Clad Facades — expansion and connection joints between metal cladding panels
• Structural Glazing — weather sealing for glass curtain walls (non-structural)
• Building Facade Joints — exterior joints subject to wind, rain and structural movement
• High Temperature Environments — high-temperature joint sealing

Why Choose SikaHyflex 305 AP

SikaHyflex-305 AP is a silicone-based sealant offering key advantages over polyurethane (PU) sealants like Sikaflex Construction: wider service temperature range, superior weathering resistance, and higher movement capability. The neutral-cure formula will not corrode metal substrates, making it particularly suitable for aluminium curtain walls. However, note that silicone sealants are not paintable — if joints need to be painted to match, choose a PU-based Sikaflex product instead.

Packaging

Cartridge. Available colours: Black, Grey (other colours available on order)

Basic Specifications

Important Notes

• Not paintable — if paint colour matching is needed, use a PU-based sealant (e.g. Sikaflex Construction)
• Not suitable for natural stone
• Not suitable for stressed polyacrylate or polycarbonate (may cause environmental stress cracking)
• Not suitable for swimming pools or surroundings
• Not suitable for joints under hydrostatic pressure or permanent water immersion
• Not suitable for bituminous substrates, natural rubber, or materials that may bleed oils, plasticisers or solvents
• EPDM gaskets require compatibility testing
• Uncured product must not contact alcohol-based products
• Colour variation due to chemicals or extreme environments is normal and does not affect performance

For detailed application methods, coverage rates and technical parameters, please refer to the official product data sheet.