Description
High-Performance Thermoplastic Roof Sealant for Demanding Jobs
Sikaflex® NP-125 is a professional-grade, one-component thermoplastic roof sealant that delivers strong, long-lasting adhesion without the need for mixing or priming. Because it bonds tenaciously to a wide range of construction substrates, it is widely used in residential and commercial roofing applications.
Additionally, the fast tack-free time allows work to continue efficiently, while full performance properties are achieved within approximately seven days under normal conditions. As a result, contractors gain reliable results with minimal downtime.
Designed for Roofing, Flashings, and Expansion Joints
This versatile sealant performs exceptionally well across multiple roof systems. Therefore, it is commonly used on sheet roofing, liquid-applied roofs, metal roofs, and shingled or tiled assemblies.
Moreover, Sikaflex® NP-125 is ideal for sealing penetrations, skylight frames, termination bars, parapet expansion joints, and lap seams in metal roof systems. Because it remains flexible, it accommodates movement while maintaining a durable seal.
Broad Substrate Compatibility Without Priming
Sikaflex® NP-125 adheres to numerous common building materials without primer in most applications. Consequently, it simplifies installation while maintaining excellent adhesion.
Compatible substrates include:
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Concrete and masonry
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Clay and ceramic tile
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Aluminum and painted metals
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Wood and composite materials
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Vinyl, rubber, and acrylic glass
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Asphalt roof shingles and PVDF coatings
In addition, the sealant can be painted with most non-rigid paints once cured, allowing for a clean, finished appearance.
Reliable Performance in Exterior Environments
This thermoplastic roof sealant performs across a wide temperature range, making it suitable for exterior use in varied climates. Furthermore, it meets key industry standards, including ASTM C920 Type S, Grade NS, Class 12.5 and Federal Specification TT-S-00230C Type II, Class B.
Because curing depends on temperature and humidity, lower temperatures may extend cure time. However, proper application ensures consistent, dependable results.
Application and Installation Benefits
Sikaflex® NP-125 comes ready to use and applies easily with a professional-grade caulking gun. Apply a continuous bead sized to ensure full contact between substrates.
For roofing tile applications, apply the sealant to the downslope tile and press the upslope tile firmly into place. This method ensures proper bonding and long-term performance.
Cure times (at 75°F / 50% RH):
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Skin time: 10–15 minutes
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Full cure: approximately 2 weeks
Key Features & Benefits
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One-component formula, no mixing required
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Fast tack-free time for efficient installation
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Strong, flexible adhesion across many substrates
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Exterior-rated for all climates
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Paintable with most non-rigid coatings
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Non-sag consistency for vertical joints
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Meets ASTM C920 and federal specifications
Typical Applications
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Roof tile bonding and lap seals
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Flashings and penetration seals
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Skylight frames and reglets
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Parapet and expansion joints
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General construction sealing
