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When building elements move, the sealant must move with them. Facade panels expand, windows shift with thermal cycling, and precast joints flex under load. If your sealant can’t handle continuous, significant movement, you face premature failure and water ingress. Hi-Flex Construction provides the robust ±50% movement capability and lasting UV resistance these dynamic joints demand, maintaining integrity where standard sealants fall short.
Hi-Flex Construction is engineered to meet the extreme demands of dynamic building elements. This high-performance MS Polymer sealant specialises in sealing critical building joints like window perimeters, facade panels, and expansion joints that experience constant movement. Formulated with a low modulus and exceptional elongation, it ensures the joint seal remains intact, waterproof, and durable against environmental stresses and building movement for the long term. It’s the specification fulfilment where standard sealants are simply not enough.
Understanding these performance metrics helps specify the right product for high-movement applications:
Applying Hi-Flex Construction is straightforward. Ensure surfaces are clean, dry, and free of contaminants. Primerless adhesion is often achievable on non-porous substrates. For critical, high-performance, or highly stressed joints, prepare porous surfaces with Everflex Supaprime Sealant Primer. For non-porous surfaces, use Adheseal 50A Surface Prep. Apply the sealant at temperatures between 5°C and 40°C, filling the joint completely to avoid air entrapment.
Tool the sealant immediately after application, within approximately 10 minutes, to achieve a smooth finish. The sealant forms a skin quickly and cures at a rate of approximately 3mm per 24 hours under standard conditions (25°C and 50% humidity). Use a compatible backer rod to control sealant depth and prevent three-sided adhesion, crucial for optimal movement performance. Clean wet tools and spills with Xylene. For skin, use Adheseal Hand Wipes.
Hi-Flex Construction stands out within the MS Polymer range due to its specialist focus on extreme movement and high-performance building joints. While it is a low modulus sealant, its engineering priorities differ significantly from other products.
For applications primarily involving waterproofing membranes, bond breakers, or fillet joints, Adheseal Hi-Flex 50 Low-Modulus Waterproofing Membrane is a better fit. If your project requires an anti-pick sealant for structural bonding or XPS panels, redirect to Adheseal Hi-Flex 60 Anti-Pick Primer. For general, everyday low modulus MS Polymer sealing tasks where extreme movement is not the primary driver, Adheseal Hi-Flex LM Low-Modulus Hybrid Polymer Sealant provides an economical and effective choice. Hi-Flex Construction is specifically for the critical joints demanding proven ±50% movement and architectural non-staining performance.
Usually no—Hi-Flex Construction + achieves strong primerless adhesion on many non-porous substrates. For critical or high-exposure applications, light abrasion and surface prep are recommended, with adhesion testing prior to installation.
Aim for a ~2:1 width:depth ratio. Internal joints min 5 mm width/depth; external joints min 12 mm width. Use backer rod for joints >10 mm deep and avoid three-sided adhesion with bond-breaker tape.
| Application / Use Case | Key Benefit | Primary Trades |
|---|---|---|
| Perimeter sealing of windows | Primerless adhesion, clean tooling, UV stability | Glaziers, Builders |
| Curtain walls & facade panels | Low modulus manages thermal movement | Glaziers, Facade Contractors |
| Precast / tilt-up expansion joints | ±50% movement; durable weather seal | Builders |
| Property | Value |
|---|---|
| Material Type | Hybrid MS Polymer |
| Curing System | 2–3 mm per 24 hours at 23°C to 25°C, 50% RH |
| Colour | White (RAL 9003), Grey (RAL 7047), Black (RAL 9011) |
| Density | 1.48 ± 0.05 g/cm³ |
| Shear Strength | 0.65 MPa |
| Elongation | >600% |
| Movement Capability | ±50% |
| Shore Hardness | 29 (after 14 days) |
| Modulus | 0.41 MPa |
| Pot Life | ≈25 minutes at 23°C and 50% RH |
| Skin Time | ≈10–15 minutes at 23°C to 25°C and 50% RH |
| Application Temperature | +5°C to +40°C |
| Service Temperature | -40°C to +100°C |
| UV Resistance | 500 h – Good (meets industrial standard) |
| Chemical Resistance | Excellent to water & detergents, Moderate to diluted acids/alkalis, Petrol & oil short periods |
| Coverage Rate | 6 mm × 6 mm: 16.7 m, 10 mm × 10 mm: 6.0 m, 12 mm × 12 mm: 4.2 m, 20 mm × 10 mm: 3.0 m, Triangular 10 mm × 10 mm: 12 m |
| Substrate Compatibility | Not for long-term immersion, Pools, Aquariums, Structural glazing, Mirrors, Avoid copper/brass discolouration, Not for bituminous or EPDM, Avoid confined cure and MVTR |
| Paintability | Paintable (test first, non-flexible paints may crack) |
| VOC Content | <4% |
| Standards | Class 50 |
| Packaging | 600 mL sausage, Carton of 20 |
| Shelf Life | 12 months (original packaging) |
| Storage Conditions | Cool, Dry, 10°C to 35°C |
Here are some common examples on where Adheseal Hi-Flex Construction Plus used by our customers.
