Sika Sikalastic 680
Sika Sikalastic 680
📋 Product specifications are for reference only.
All product details should refer to the official manufacturer documents. For official product data sheets or technical enquiries, please contact us via WhatsApp.
Sikalastic 680 — Single Component Polyurethane Waterproofing Membrane
Sikalastic®-680 is a single-component, highly elastic polyurethane liquid-applied waterproofing membrane for concrete structures. It forms a continuous, seamless waterproof layer and must be covered by protective toppings (screed, tiles, or ballast). Commonly known in Hong Kong as "rooftop waterproofing black glue" (天台防水黑膠).
Key Features
- Single component — ready to use, no mixing required
- High elasticity — elongation at break > 500%
- Quick drying — tack free in approximately 4 hours (25°C / 75% RH)
- Excellent adhesion to concrete, render, and masonry (> 1 MPa)
- Good impact and abrasion resistance
- Low odour, non-toxic
- Low temperature flexibility
- Multiple application methods: brush, roller, trowel, squeegee, or airless spray
Applications
- Roofs, podiums, balconies (covered by protective toppings)
- Bathrooms, pools, tanks, green roofs, and planters
- External walls, basements, and foundations
- As water barrier under plasters, screeds, or tiles
Important: Sikalastic®-680 is designed for non-exposed use. A protective covering layer must be applied over the finished membrane.
Technical Specifications
| Property | Value |
|---|---|
| Chemical Base | Polyurethane |
| Components | Single component, ready to use |
| Colour | Black, grey |
| Density | ~1.5 kg/L (± 0.05) |
| Shore A Hardness | 60 (± 5) |
| Tensile Strength | ~2 MPa |
| Elongation at Break | > 500% |
| Tensile Adhesion Strength | > 1 MPa |
| Tear Strength | ~15 N/mm |
| Yield (Standard) | ~2.0 kg/m² (~1.3 mm wet film), one or more coats |
| Yield (Reinforced) | ~2.5 kg/m² (~1.6–1.7 mm wet film), with Sika® Glass Fabric |
| Tack Free Time | ~4 hours (25°C, 75% RH) |
| Ambient Temperature | +5°C to +40°C |
| VOC Content | ≤ 250 gm/L (HK Air Pollution Control — Roof coatings, non-exposed) |
| Packaging | 20 kg pail |
| Shelf Life | 9 months from date of production |
| Storage | Unopened, cool and dry, away from sunlight and frost |
Product Comparison
| Product | Type | Exposed Use | Elasticity | Best For |
|---|---|---|---|---|
| Sikalastic 680 | Polyurethane | Must be covered | High (> 500%) | Roofs / basements / pools — under tiles or screed |
| SikaFill C | Acrylic | Can be exposed | High | Village rooftops / walls — economical choice |
| Nitoproof 600PF | Polyurethane | Must be covered | High | Large projects — requires protective screed |
| Hyperdesmo Classic | Polyurethane | Can be exposed | Very high | Premium projects — 30-year brand |
FAQ
Can Sikalastic 680 be left exposed?
No. According to the product data sheet, Sikalastic®-680 is designed for non-exposed applications and must be covered by a protective layer such as screed, tiles, or ballast. For exposed waterproofing solutions, consider SikaFill C (acrylic) or Hyperdesmo Classic (exposed-grade polyurethane).
How long before a flood test can be carried out?
Allow at least 3 days of drying at 25°C and 75% relative humidity before flood testing. In cooler or more humid conditions, drying time will be longer and the waiting period should be extended accordingly.
