Sika Sikalastic 591
Sika Sikalastic 591
Sikalastic®-590 is a one-component waterborne liquid applied roof waterproofing membrane based on polyurethane modified acrylic dispersion, with improved ponding water capability. Ready to use with no flame required. Features high elasticity (~360% elongation), excellent UV resistance and anti-yellowing performance, and passed 1,000-hour artificial weathering testing. The white version achieves ~80% solar reflectance and SRI ~101. Suitable for roof waterproofing in new construction and refurbishment, particularly for roofs where short-term ponding may occur.
Sikalastic-590 — Liquid Roof Waterproofing with Improved Ponding Water Capability
Sikalastic®-590 is a one-component polyurethane-acrylic dispersion waterborne liquid waterproofing membrane with improved water ponding resistance. It is ready to use and can be applied manually or by spray, either as a coating or as a reinforced liquid applied membrane system. It features excellent UV resistance, anti-yellowing performance and good crack-bridging capacity, forming a seamless elastic waterproofing membrane.
Key Features
- Good behavior under limited water ponding (improved formulation)
- UV resistant and resistant to yellowing and weathering
- Highly elastic and crack-bridging (~360% elongation at break)
- Non-toxic and VOC compliant water-based coating
- One component — ready to use
- Excellent adhesion on porous and non-porous substrates
- Seamless waterproofing membrane — no joints or laps
- Water vapour permeable — allows the substrate to breathe
- Passed 1,000-hour artificial weathering test (ASTM G154, UVA-340) — no cracking, blistering, delamination or chalking
Applications
- Roof waterproofing — liquid applied waterproofing for new construction and refurbishment projects
- Complex roofs — roofs with many details, complex geometry or limited accessibility
- Roof life extension — cost efficient life cycle extension of failing roofs
- Reflective coating — white version enhances energy efficiency by reducing cooling costs
Why Choose Sikalastic-590?
Sikalastic-590 is a liquid roof waterproofing membrane in the Sika range with improved ponding water capability, suitable for roofs where drainage conditions may not be ideal:
- Improved ponding water capability: Better resistance to short-term ponding water compared to standard liquid membranes, suitable for roofs with minor water accumulation
- UV and anti-yellowing: Excellent weathering resistance, passed 1,000-hour accelerated weathering test, white version resists yellowing
- High elasticity: ~360% elongation at break — effectively bridges substrate cracks
- Energy efficiency: White version achieves ~80% solar reflectance and SRI ~101, reducing roof surface temperature and cooling costs
- Sika brand: Swiss Sika — over 100 years of proven quality and reliability
For other roof waterproofing solutions, browse our roof waterproofing range.
Packaging
| Item | Specification |
|---|---|
| Packaging | 20 kg plastic pails |
| Colours | Grey and white |
| Shelf Life | 12 months from date of production (store properly in original, unopened, undamaged sealed packaging in dry conditions) |
Technical Specifications
| Parameter | Value |
|---|---|
| Chemical Base | Polyurethane modified acrylic dispersion (waterborne) |
| Density | ~1.32 kg/l at +30°C |
| Tensile Strength (free film, > 7 days) | ~1.7 N/mm² (ASTM D412) |
| Elongation at Break (free film) | ~360% (ASTM D412) |
| Adhesion in Peel (free film, > 7 days) | ~1.5 N/mm² (ASTM D7234) |
| Solar Reflectance (white) | ~80% (ASTM E903-12) |
| Thermal Emittance (white) | ~0.91 (ASTM C1371-15) |
| Solar Reflectance Index (white) | ~100.9 (ASTM E1980-11) |
| Artificial Weathering | Pass, 1,000 hours UVA-340 (ASTM G154) — no cracking, blistering, delamination, chalking |
Consumption
Waterproofing Without Reinforcement (Roof Refurbishment / Reflective Coating)
| Layer | Product | Consumption |
|---|---|---|
| Primer coat | Sikalastic-590 diluted with 10% water / Sikafloor-161 / Sikafloor-156 | ~0.3 kg/m² |
| First coat | Sikalastic-590 | ~0.5 kg/m² |
| Second coat | Sikalastic-590 | ~0.5 kg/m² |
Waterproofing With Reinforcement (New Construction & Refurbishment)
| Layer | Product | Consumption |
|---|---|---|
| Primer coat | Sikalastic-590 diluted with 10% water / Sikafloor-161 / Sikafloor-156 | ~0.3 kg/m² |
| First coat | Sikalastic-590 | ~0.3 kg/m² |
| Second coat | Sikalastic-590 | ~0.6 kg/m² |
| Reinforcement membrane | Sikalastic® Fleece-80 / Sika® Glass Fabric -55G | 1 m² |
| Third coat | Sikalastic-590 | ~0.5 kg/m² |
| Final coat | Sikalastic-590 | 0.3–0.5 kg/m² |
Application Conditions and Drying Times
| Parameter | Value |
|---|---|
| Application Temperature (ambient & substrate) | +15°C to +35°C |
| Max. Relative Humidity | 80% r.h. |
| Substrate Moisture Content | < 6% |
| Dew Point | Surface temperature must be at least 3°C above dew point |
| Drying Stage | +20°C / 50% r.h. | +30°C / 50% r.h. |
|---|---|---|
| Touch Dry | Approx. 2 hours | Approx. 1 hour |
| Rain Resistant | Approx. 10 hours | Approx. 6 hours |
| Fully Cured | Approx. 4 days | Approx. 2 days |
Important Notes
- Sikalastic-590 can be applied on roofs subject to short-term ponding water — recommended slope of at least 1% (minimum 0.5% depending on roof layout and drain availability)
- Protect applied material from rain until 24 hours after application to achieve good ponding water capability
- Do not apply on substrates with rising moisture
- Always apply during falling ambient and substrate temperature — application during rising temperatures may cause "pin holing" from rising air (outgassing)
- Temperature must not drop below 15°C and humidity must not exceed 80% r.h. until membrane has fully cured
- Ensure each layer is totally dry and the surface is without pinholes before applying any top coat
- Do not allow temporary ponding between coats or until the final coating has totally cured — brush or mop surface water away
- In cold climatic zones, do not apply on roofs subject to ponding water with subsequent freezing — provide slope of at least 3%
- Do not apply directly on insulation boards — use a separation layer between insulation board and Sikalastic-590
- Sikalastic-590 is an exposed system — do not overcoat with tile, concrete or others
- Sikalastic® Fleece-80 / Sika® Glass Fabric -55G can be used as total reinforcement or for partial reinforcements over dynamic cracks and joints
- Clean all tools and equipment with water immediately after use
FAQ
What is the difference between Sikalastic-590 and Sikalastic-560?
Sikalastic-590 has improved short-term ponding water capability, making it more suitable for roofs where drainage conditions may not be ideal and minor water accumulation may occur. Sikalastic-560 is not suitable for ponding water conditions. Additionally, Sikalastic-590 has a higher minimum application temperature (+15°C vs +8°C for 560) and shorter shelf life (12 months vs 18 months for 560). Both are waterborne liquid membranes with similar chemical bases.
Can Sikalastic-590 withstand permanent water immersion?
No. Sikalastic-590 has improved short-term ponding water resistance but is not suitable for permanent or long-term water immersion. Roofs should maintain a minimum slope of 1% to ensure proper drainage.
Does the white Sikalastic-590 provide heat reflection?
Yes, the white version achieves ~80% solar reflectance and SRI ~101, effectively reflecting solar heat to reduce roof surface temperature and building cooling costs. It has passed 1,000-hour artificial accelerated weathering testing with excellent anti-yellowing performance.
What is the coverage of Sikalastic-590?
Unreinforced system (primer + 2 coats): total approx. 1.3 kg/m². Reinforced system (primer + 4 coats + reinforcement): total approx. 2.0–2.2 kg/m². A 20 kg pail covers approximately 15 m² for the unreinforced system. Actual coverage depends on substrate conditions.
How much does Sikalastic-590 cost?
Please WhatsApp us for the latest Sikalastic-590 pricing. We offer self-pickup from our Mong Kok store and Hong Kong delivery service.
