Sikalastic-1K is a one-component, fibre-reinforced flexible cementitious waterproofing mortar for concrete protection and wet-area waterproofing. Mix with water and apply by brush, trowel or suitable spray equipment over correctly prepared mineral substrates.
Use Sikalastic-1K for bathrooms and showers beneath tiles, balconies and terraces, concrete tanks and basins, swimming pools beneath a suitable protective finish, below-ground walls and suitable positive- or negative-side waterproofing applications. It is also used to protect reinforced concrete against carbonation and water ingress.
The system provides at least 0.75 mm crack bridging under the stated EN 14891 test conditions. Performance testing includes no water penetration at 5.0 bar positive pressure and 2.5 bar negative pressure under specified laboratory conditions. These are tested values, not a substitute for correct membrane detailing or structural design.
Apply in at least two coats and build the required system thickness: typically 2 mm dry film thickness for standard applications and 3–4 mm for negative pressure or immersion. Substrates may be damp but must be sound and correctly prepared. Protect fresh work from rain for 24–48 hours, and avoid applying in direct sun, strong wind or imminent rain.
Where drinking-water contact is specified, follow the complete curing and washing procedure before filling. Swimming-pool applications require the appropriate protective or tiled finish. Compare other systems in our cementitious waterproofing membrane range.
What is Sikalastic-1K used for?
Flexible waterproofing and concrete protection on tanks, wet areas, balconies, pools before tiling, below-ground walls and other compatible mineral structures.
Can it be applied to damp substrates?
Yes. The current Australian PDS specifically lists application to damp substrates.
How is it applied?
By brush, spray or trowel in multiple layers to the required total thickness.
Is it suitable for potable-water contact?
The current Australian PDS lists AS/NZS 4020:2005 testing for products in contact with drinking water.
| Property | Value |
|---|---|
| Composition | Cement modified with alkali resistant polymers, selected aggregates, fine fillers, admixtures, and fibres |
| Shelf Life | 6 months from date of production |
| Crack Bridging Ability | ≥0.75 mm (EN 14891 A.8.2/A.8.3 at +23°C and -5°C for 3.6 kg/m² in 2 layers) |
| Tensile Adhesion Strength | ≥0.8 N/mm² initial (EN 1542, 3 mm in 2 layers at 22% water); ≥0.5 N/mm² after water contact, heat ageing, freeze-thaw, lime and chlorinated water (EN 14891 A.6.3–A.6.9, 3.6 kg/m² in 2 layers at 30% water). |
| Capillary Absorption | ~0.02 kg/m²·h0.5 (3 mm layer, 22% water) |
| Water Penetration (Positive Pressure) | No penetration after 72h at 5.0 bar (3 mm layer, 22% water); No penetration after 7 days at 1.5 bar (3.6 kg/m²) |
| Water Penetration (Negative Pressure) | No penetration after 72h at 2.5 bar (3 mm layer, 22% water) |
| Permeability to Water Vapour | Class I (permeable), SD < 5 m |
| Permeability to Carbon Dioxide | SD ≥ 50 m |
| Freeze-Thaw De-icing Salt Resistance | ≥0.8 N/mm² (3 mm layer, 22% water) |
| Reaction to Fire | Euroclass A2 |
| Density | ~1.5 kg/l |
| Pot Life | ~30 min at +20 °C |
| Coverage Rate | ~1.2 kg/m²/mm |
| Minimum Layer Thickness (Standard) | 2 mm DFT (minimum 2 layers) |
| Minimum Layer Thickness (Negative Pressure/Immersed) | 3-4 mm DFT (minimum 2 layers) |
| Maximum Thickness per Layer (Trowel) | 2 mm |
| Maximum Thickness per Layer (Brush) | 1 mm |
| Ambient Temperature | 5 °C min. / 35 °C max. |
| Substrate Temperature | 5 °C min. / 35 °C max. |
| Waiting Time - Horizontal Tiling (20°C) | ~2 days |
| Waiting Time - Horizontal Tiling (10°C) | ~7 days |
| Waiting Time - Vertical Tiling (20°C) | ~2 days |
| Waiting Time - Vertical Tiling (10°C) | ~3 days |
| Waiting Time - Water Emulsion Coating (20°C) | ~2 days |
| Waiting Time - Water Emulsion Coating (10°C) | ~3 days |
| Waiting Time - Water Immersion (20°C) | ~2 days |
| Waiting Time - Water Immersion (10°C) | ~7 days |
| Waiting Time - Drinking Water Contact (20°C) | ~15 days |
| Waiting Time - Drinking Water Contact (10°C) | ~15 days |
| Water Dosage - Brush Application (per 20kg) | ~6.0 litres |
| Water Dosage - Trowel Application (per 20kg) | ~4.4 litres |
| Storage Conditions | Store properly in the original packaging, in cool and dry conditions. Protect from water. |
| Bond Strength | ≥0.5 N/mm² initial tensile adhesion (EN 14891 A.6.2; 3.6 kg/m² in two layers at 30% water). |
| Heat Aging | ≥0.5 N/mm² tensile adhesion after heat ageing (EN 14891 A.6.5; 3.6 kg/m² in two layers at 30% water). |
| Thickness | For standard applications a total 2mm DFT, applied in minimum 2 layers.; For negative pressure/immersed applications a total 3-4mm DFT, applied in minimum 2 layers.; Maximum recommended thickness per layer is 2 mm when applied by trowel and 1 mm when applied by brush. |
Here are some common examples on where Sikalastic®-1K used by our customers.
