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At a Glance: Key Applications
Use Adheseal PU15 for: Sealing perimeter window and door frames, expansion joints in precast and tilt-up panels, curtain walls, and other high-movement facade applications where a soft, flexible seal is critical.
Adheseal PU15: A Technical Overview
Adheseal PU15 is a high-performance, single-component, low modulus polyurethane sealant, specifically engineered for sealing dynamic joints in modern building facades. As a low modulus sealant, it is exceptionally soft and flexible, allowing it to accommodate significant joint movement while exerting minimal stress on the substrate and the bond line. This makes it the preferred choice for fenestration details and sealing joints around powder-coated aluminium frames, precast panels, and other materials subject to thermal expansion and contraction. Its robust formulation cures on exposure to atmospheric moisture to form a tough, durable, and highly elastic seal with excellent resistance to weathering, making it a reliable, long-term solution for the entire building envelope.
Comparative Performance Overview
| Metric | Adheseal PU15 (Low Modulus) | Standard PU Sealant (Mid-High Modulus) | Advantage |
|---|---|---|---|
| Modulus of Elasticity | 0.2 MPa @ 100% | >0.4 MPa | The lower modulus means the sealant requires less force to stretch, imposing minimal stress on the adhesive bond line and making it ideal for sensitive substrates like powder coatings. |
| Elongation at Break | >2200% | ~600-800% | Exceptional elongation provides an enormous safety factor against cohesive failure (splitting) in joints that experience extreme or unanticipated movement. |
| Hardness (Shore A) | 15 | 25-40 | The softer, more flexible nature of the cured sealant allows it to better accommodate cyclical movement without fatigue, ensuring long-term joint integrity. |
| Primary Application | High-movement facade joints | General purpose, floor joints | Purpose-engineered for the specific demands of facade and window perimeter joints, ensuring optimal performance where flexibility is the key requirement. |
Using Adheseal PU15 in a Complete System
Adheseal PU15 is designed as the primary weather seal in high-performance facade and fenestration systems. As specified in major projects like the Peregian Springs Shopping Centre, it is used to create the flexible seal between window/door frames and the building structure. Within a waterproofing system, it functions as the compatible sealant for joints and penetrations that are subject to movement, applied over a backing rod or bond-breaker before the main membrane is installed. This ensures the entire system can accommodate structural movement without compromising the waterproof barrier.
How Adheseal PU15 Prevents Common Failures
Common failure prevention information
Failure Mode: Adhesive Failure on Powder Coated Aluminium
As a low modulus sealant, PU15 exerts very little stress on the bond line as it stretches and compresses. This prevents the sealant from peeling away from sensitive substrates like powder coatings or paints, which can be pulled apart by higher modulus sealants under movement.
Failure Mode: Sealant Splitting in Wide or High-Movement Joints
With an extreme elongation at break of over 2200%, PU15 offers an unparalleled safety margin against cohesive failure. It can stretch to many times its original width before splitting, ensuring a continuous, weatherproof seal even in poorly designed or unexpectedly large movement joints.
Failure Mode: Loss of Seal due to Weathering
Adheseal PU15 has been tested beyond the requirements of ASTM C793 and ISO 11431 for accelerated UV and weather resistance. It maintains its flexibility and adhesion after prolonged exposure, preventing the seal from becoming hard, brittle, and failing over time.
Core Features & Specifications
- Low Modulus Formulation: Cures to a soft, highly flexible sealant (Shore A 15) that accommodates movement while placing minimal stress on the substrate and bond line.
- Exceptional Movement Capability (±30%): Provides a highly elastic seal capable of handling significant cyclical expansion and contraction in facade joints.
- Extreme Elongation (>2200%): Offers a massive safety factor against cohesive failure, ensuring the sealant remains intact even under extreme stress.
- Excellent UV & Weathering Resistance: Independently tested to withstand long-term exposure to harsh climates without cracking or significant degradation.
- Paintable Surface: Can be painted with a wide range of acrylic, oil, and rubber-based paints to seamlessly match facade colours (testing recommended).
- Low VOC Formulation: Meets "Green Star" environmental criteria, making it suitable for modern, environmentally conscious building projects.
The Adheseal PU15 Advantage
- Protect Sensitive Substrates: The low modulus design prevents damage and delamination on powder coatings, paints, and other sensitive facade materials.
- Engineer Fail-Safe Joints: The extreme elongation capacity provides confidence that the seal will hold, even in joints with higher-than-expected movement.
- Achieve Long-Term Weather Sealing: Rely on a sealant with proven resistance to the harsh Australian climate, ensuring a durable, flexible seal that won't become hard or brittle.
- Simplify Specification for Facades: Use the sealant specifically engineered and preferred for fenestration details, ensuring the right balance of flexibility and durability for window and door perimeters.
Applications in Practice: Trade Scenarios
For Facade & Fenestration Contractors: Sealing a Window Perimeter Joint
The Engineering Challenge: To create a durable, weatherproof seal between a powder-coated aluminium window frame and a precast concrete panel, which will experience significant differential thermal movement.
The System-Based Solution with Adheseal PU15: After priming the concrete with Supaprime and cleaning the aluminium with 50A Surface Prep, install a backing rod to the correct depth. Apply Adheseal PU15 and tool to a smooth finish. The sealant's low modulus will accommodate the movement without stressing the powder coating, while its high elongation provides a long-lasting, flexible seal.
Best Practice Note: Always use a bond breaker (backing rod or tape) to ensure two-sided adhesion. Three-sided adhesion will restrict the sealant's ability to move and can lead to premature failure.
For Remedial Builders: Replacing Failed Facade Sealants
The Engineering Challenge: Existing sealant in the movement joints of a tilt-up panel building has failed due to excessive movement or UV degradation, requiring a high-performance replacement.
The System-Based Solution with Adheseal PU15: Remove all failed sealant and backing material, then grind the joint edges clean. Install new, correctly sized backing rod and prime with Supaprime. Fill the joint with Adheseal PU15. Its ±30% movement capability and superior UV resistance will provide a significantly more durable and long-lasting repair compared to a standard sealant.
Best Practice Note: Ensure the joint width-to-depth ratio is approximately 2:1. For a 20mm wide joint, the backing rod should be set to create a 10mm deep sealant reservoir for optimal performance.
Certifications & Regulatory Compliance
Adheseal PU15 is formulated and tested to meet the performance requirements of international standards for high-performance construction sealants. It has been tested beyond the requirements of ASTM C793-05 and ISO 11431 for accelerated UV and weathering resistance. Fire performance has been tested in general accordance with AS/NZ 3837:1998, where it was noted to intumesce when exposed to a 60 kW/m² irradiance. Its low VOC formulation (95 g/L) meets Green Star environmental criteria.
Storage & Shelf Life Considerations
To maintain product quality, store Adheseal PU15 in a cool, dry location between 10°C and 35°C. Keep in original, unopened packaging, protected from direct sunlight and moisture. When stored correctly, the product has a shelf life of 12 months from the date of manufacture.
Frequently Asked Questions About Adheseal PU15
Q: What is the main difference between PU15 and PU25 FC?
A: PU15 is a low modulus sealant, meaning it is very soft and flexible (Shore A 15) and designed for high-movement facade joints like window perimeters. PU25 FC is a higher modulus, general-purpose sealant that is tougher (Shore A 25) and better suited for applications like floor joints or as an adhesive.
Q: Why is a "low modulus" sealant better for window frames?
A: Window frames, especially powder-coated aluminium, expand and contract significantly with temperature. A low modulus sealant like PU15 can stretch easily with this movement, putting very little stress on the paint or powder coat. A harder, higher modulus sealant can exert enough force to peel the coating off the frame over time.
Q: Is this product fire rated?
A: Adheseal PU15 has been tested to AS/NZ 3837, a reaction-to-fire test. During the test, it was observed to intumesce (swell up to form a protective char), which is a beneficial characteristic in a fire. However, it does not carry a specific fire-resistance level (FRL) on its own; this depends on the overall system it is installed in.
Q: How long do I have to tool the sealant after application?
A: Tooling must be completed before the sealant forms a skin. For PU15, the tack-free time is around 4 hours at 23°C, but you should aim to tool the joint within 10-20 minutes of application for the best results. Higher temperatures and humidity will shorten this time.
Applications & Benefits
| Application / Use Case | Key Benefit | Primary Trades |
|---|---|---|
| Perimeter Sealing of Windows & Doors | Low modulus prevents stress on frames and coatings; specified for fenestration. | Facade Contractors, Glaziers, Carpenters |
| Expansion Joints in Precast & Tilt-Up Panels | Accommodates high movement (±30%) and resists weathering for long-term facade integrity. | Builders, Concreters, Remedial Contractors |
| Sealing Curtain Walls | Exceptional elongation (>2200%) provides a robust seal against wind and rain. | Facade Engineers, Specialist Contractors |
| Metal Cladding & Bolted Lap Joints | Excellent adhesion to metals and provides a flexible, waterproof seal. | Roofers, Cladding Installers, Plumbers |
| Waterproofing System Detailing | Provides the flexible joint sealant component in NCC-compliant waterproofing systems. | Waterproofers, Remedial Contractors |
Applying Adheseal PU15: Protocols & Best Practices
General Application Steps:- Preparation: Ensure the joint is clean, dry, and correctly prepared with backing rod and primer as per the Adhesion & Preparation Guide. Mask adjacent surfaces with tape for a professional finish.
- Application: Cut the nozzle at a 45° angle to the desired bead size. Using a sausage gun, apply the sealant by pushing the bead ahead of the nozzle, ensuring it is forced firmly into the joint for full contact with both sides.
- Tooling: Within 10-20 minutes of application, tool the sealant with a dry spatula or tool to create a smooth, concave surface. This ensures the sealant is well-compacted and has maximum adhesion.
- Finishing: Remove the masking tape immediately after tooling, while the sealant is still wet, pulling it away from the joint. Clean up any excess uncured sealant with Xylene.
For Facade & Fenestration Contractors: Sealing a Window Perimeter Joint
The Engineering Challenge: To create a durable, weatherproof seal between a powder-coated aluminium window frame and a precast concrete panel, which will experience significant differential thermal movement.
The System-Based Solution with Adheseal PU15: After priming the concrete with Supaprime and cleaning the aluminium with 50A Surface Prep, install a backing rod to the correct depth. Apply Adheseal PU15 and tool to a smooth finish. The sealant's low modulus will accommodate the movement without stressing the powder coating, while its high elongation provides a long-lasting, flexible seal.
Best Practice Note: Always use a bond breaker (backing rod or tape) to ensure two-sided adhesion. Three-sided adhesion will restrict the sealant's ability to move and can lead to premature failure.
For Remedial Builders: Replacing Failed Facade Sealants
The Engineering Challenge: Existing sealant in the movement joints of a tilt-up panel building has failed due to excessive movement or UV degradation, requiring a high-performance replacement.
The System-Based Solution with Adheseal PU15: Remove all failed sealant and backing material, then grind the joint edges clean. Install new, correctly sized backing rod and prime with Supaprime. Fill the joint with Adheseal PU15. Its ±30% movement capability and superior UV resistance will provide a significantly more durable and long-lasting repair compared to a standard sealant.
Best Practice Note: Ensure the joint width-to-depth ratio is approximately 2:1. For a 20mm wide joint, the backing rod should be set to create a 10mm deep sealant reservoir for optimal performance.
Limitations & Safety
Product limitations and safety information
Limitations:
- Not suitable for use in totally confined spaces as the sealant requires atmospheric moisture to cure.
- Not for internal swimming pool use or areas with high chlorine exposure.
- Not recommended for structural glazing, composite panels, or direct contact with natural stone where staining could be a concern.
- Avoid use on bituminous or EPDM rubber surfaces. May discolour copper and brass.
Safety & Handling:
- Hazard: May cause an allergic skin reaction and may cause allergy or asthma symptoms if inhaled.
- PPE: Wear protective gloves (Nitrile Rubber recommended), safety glasses, and suitable respiratory protection in areas with inadequate ventilation.
- Ventilation: Use with adequate ventilation. If an inhalation risk exists, an organic vapour/particulate respirator is required.
- Handling: Avoid breathing vapours and contact with skin. Contaminated work clothing should not be allowed out of the workplace.
Adheseal PU15 Adhesion & Preparation Guide
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Substrate preparation guidelines
- General Principle: Surfaces must be structurally sound, dry, and clean of all contaminants such as dust, oil, grease, and form release agents that can hinder adhesion.
- Porous Substrates (Concrete, Masonry, Brick): Ensure surfaces are free of laitance. For critical, high-performance facade applications, prime the joint edges with Everflex Supaprime and allow to dry for 30 minutes to 2 hours before sealing.
- Non-Porous Substrates (Aluminium, Powder Coat, PVC): Clean thoroughly using a two-wipe process with a suitable solvent. For optimal, long-term adhesion, pre-treat with Adheseal 50A surface prep. A light abrasion with a fine pad is also recommended.
- Joint Design: To allow for movement, the joint must have two-sided adhesion only. Install an open-cell backing rod (25% larger than the joint width) to control depth and prevent three-sided adhesion.
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