Sika Sikaplan WP 1120-20HL
Sika Sikaplan WP 1120-20HL
Sikaplan® WP 1120-20 HL — PVC Waterproofing Membrane for Underground Structures
Sikaplan® WP 1120-20 HL is a homogeneous PVC-P (polyvinylchloride) sheet waterproofing membrane with a yellow signal layer, designed for waterproofing tunnels, basements, shafts, and all kinds of below-ground structures against groundwater. The 2.0 mm thick membrane is installed by loose laying, mechanical fastening, or ballasting, with all overlaps heat welded. Installation must be carried out by Sika-trained contractors.
Key Features
- Virgin PVC-P material — consistent quality homogeneous sheet
- Yellow signal layer to indicate membrane damage during inspection
- High tensile strength: MD 17.0 / CMD 16.0 N/mm² (EN 12311-2)
- High elongation: ≥ 300% in both directions
- Tear strength ≥ 500 N (nail shank, EN 12310-1)
- Foldable at low temperatures down to -25 °C
- Resistant to natural aggressive mediums in ground water and soil
- High mechanical impact resistance ≥ 750 mm (EN 12691)
- Dimensional stability ≤ 2% change after heat (EN 1107-2)
- Can be installed on damp and weak substrates
- Eco-Product Directory listed (Application No: PL-00975-2021)
Applications
- Tunnel waterproofing (including cut and cover tunnels)
- Basement and below-ground structure waterproofing
- Shaft waterproofing
- Protection against groundwater ingress
Technical Specifications
| Property | Value | Standard |
|---|---|---|
| Material Base | PVC-P (homogeneous sheet) | — |
| Overall Thickness | 2.0 mm (-5/+10%) | EN 1849-2 |
| Mass per Unit Area | ~2.600 kg/m² (-5/+10%) | EN 1849-2 |
| Roll Dimensions | 2.0 m (W) × 15.0 m (L) | — |
| Roll Weight | ~78 kg | — |
| Tensile Strength (MD / CMD) | 17.0 (±2.0) / 16.0 (±2.0) N/mm² | EN 12311-2 |
| Elongation (MD / CMD) | ≥ 300% / ≥ 300% | EN 12311-2 |
| Tear Strength (Nail Shank) | ≥ 500 N | EN 12310-1 |
| Impact Resistance | ≥ 750 mm | EN 12691 |
| Static Load Resistance | ≥ 20 kg | EN 12730 Method B |
| Foldability at Low Temperature | -25 °C | EN 495-5 |
| Water Tightness | Pass | EN 1928 B |
| Dimensional Change After Heat | ≤ 2% | EN 1107-2 |
| Reaction to Fire | Class E | EN 13501-1 |
| Exposure to Bitumen | No performance determined | EN 1548 |
| Application Temperature | +5 °C to +35 °C | — |
| Shelf Life | 5 years (unopened, original packaging) | — |
Limitations
- Installation by Sika-trained contractors only
- Not UV stabilized — cannot be permanently exposed to sunlight
- Not resistant to permanent contact with bitumen or non-PVC plastics; separation layer (PP geotextile ≥ 150 g/m²) required
- Special precautions required below +5 °C or above 80% RH
- Ensure adequate ventilation when heat welding in enclosed spaces
FAQ
Can Sikaplan WP 1120-20HL be used for rooftop or exterior waterproofing?
No. This product is designed exclusively for underground structures (tunnels, basements, shafts). It is not UV stabilized and cannot be permanently exposed to sunlight. Use other Sika waterproofing products for exposed applications.
How are the membrane sheets joined?
All overlaps must be heat welded using hand welding guns (e.g., Leister Triac PID) or automatic machines (e.g., Leister Twinny S / Triac Drive). Welding parameters must be established through on-site trials before production welding. T-joints require special preparation with chamfered overlaps.
Can it be installed on a damp substrate?
Yes. Sikaplan WP 1120-20HL can be installed on damp substrates, which is one of its key advantages. Installation methods include loose laying, mechanical fastening, or ballasting as appropriate.
