Sikalastic®-1 KMY
Sikalastic®-1 KMY is a one component, flexible, fiber-reinforced mortar, based on cement modified with special alkali-resistant polymers. It also contains fine fillers, selected graded aggregates, plus special waterproofing additives to produce a flexible mortar that is ideal for waterproofing surfaces subject to flexural strain.
- Easy to apply by brush, roller or trowel
- Can be applied on damp substrate
- Good sag resistance and easy to apply on vertical surfaces
- Flexible crack-bridging properties
- Very good adhesion to most common substrates (concrete, cementitious mortar, stone, bricks, ceramic and timber)
- Mixing ratio can be adjusted in order to obtain the consistency and workability

Usage
- Waterproof protection of concrete structures including tanks, basins, pipes, swimming pools
- Waterproofing external wall surfaces to be backfilled in the ground
- Internal waterproofing of walls and floors, in basements, etc
- Waterproofing of terraces and balconies over concrete or prepared existing tiles
- General waterproofing of concrete surfaces
- Compatible with SikaCeram® series, tilling system
Advantages
- Easy to apply by brush, roller or trowel
- Can be applied on damp substrate
- Good sag resistance and easy to apply on vertical surfaces
- Flexible crack-bridging properties
- Very good adhesion to most common substrates (concrete, cementitious mortar, stone, bricks, ceramic and timber)
- Mixing ratio can be adjusted in order to obtain the consistency and workability
Packaging
- 20 kg bag
- 2 pack x 6 kg in pail
Colour
Grey powder
Product Details
APPROVALS / STANDARDS
- SPAN Approval: SPAN/PPI/1683-2016 (Potable Water)
- SINGAPORE GREEN LABEL: 032-118-3205 "Environmentally Preferred Coating"
Composition
Cement modified with polymers, selected aggregates, admixtures, additives and fibers.
Shelf Life
6 months from date of production
Storage Conditions
Store properly in dry conditions, in undamaged and unopened, original sealed packaging. Protect from direct sunlight, rain and water. Not sensitive to frost.
Tensile Strength
2.0 N/mm² | (ASTM D412) |
Tensile Adhesion Strength
On concrete, 28 days
Dry substrate | ~1.3–1.5 N/mm² |
Crack Bridging Ability
≥ 0.50 mm | (EN 1062-7) |
≥ 0.75 mm Class A3 | (EN 14891 A.8.2) |
Application
Mixing Ratio
Application by roller | ~7.0 L water per 20 kg bag / ~2.1 L water per 6 kg bag |
Application by brush | ~6.0 L water per 20 kg bag / ~1.8 L water per 6 kg bag |
Application by trowel | ~4.4 L water per 20 kg bag / ~1.3 L water per 6 kg bag |
Fresh Mortar Density
~1.5 kg/l (at +25 °C)
Ambient Air Temperature
+5 °C min. / +40 °C max.
Substrate Temperature
+5 °C min. / +40 °C max.
Pot Life
~30 minutes (at +23 °C)
Waiting Time / Overcoating
Sikalastic®-1 KMY must be completely hardened before over-coating or water contact.
Guide for waiting times at +20 °C:
Horizontal coving by tiles | ~2 days |
Vertical covering by tiles | ~2 days |
Water emulsion coating | ~2 days |
Immersion in water | ~2 days |
Contact with drinkable water | ~15 days |
Times will vary due to ambient and substrate humidity.
Consumption
This depends on the substrate roughness; as a guide, ~1.0 kg/m²/mm
Sikalastic®-1 KMY must be applied in minimum 2 coats
Wet areas such as toilets, balconies: 2.0 kg/m²
Critical areas such as swimming pools, ponds: 3.0 kg/m²
MIXING
Sikalastic®-1 KMY should be mechanically mixed using a forced-action mixer or in a clean drum using a low speed electric drill and paddle mixer (maximum 500 r.p.m.). Mix slowly by adding Sikalastic®-1 KMY into the water (For the quantity of water, see mixing ratio). Once a homogeneous mix is obtained, continue to mix for another 3–4 min. The mortar must be completely homogeneous and free from lumps. Do not add any other additives. Mix the whole bag, in order to avoid any inadequacy in the distribution of the constituents.
Do not use a free-fall mixer to mix Sikalastic®-1 KMY.
APPLICATION
Trowel
Maintain an even pressure onto the substrate's surface to ensure a uniform distribution and thickness of Sikalastic®-1 KMY. Trowel in two directions (at right angles). Maximum recommended thickness is 2 mm per coat. The final thickness when applied by trowel will depend on the method of application and level or grade of exposure / waterproofing required. The highest waterproofing performance is obtained by applying Sikalastic®-1 KMY using a trowel in at least 2 coats, to a total thickness of 3–4 mm.
*Spray application is applicable with the correct equipment. Please consult Sika’s representative for more information.
Brush or Roller
Application by brush or roller must be undertaken with maximum attention to completely cover the substrate's surface uniformly. Brush or roll in two directions (at right angles). The maximum recommended thickness for these method of application is 1 mm per coat. In these situation, the application of min. 2–3 coats is required.
Joints / Critical areas
At floor joints and other critical areas (for example, any junctions with vertical surfaces), the watertightness can be reinforced by using Sika® SealTape-F. Sika® SealTape-F must be fixed directly onto the first coat of Sikalastic®-1 KMY whilst it is still wet, and then covered by a second coat of Sikalastic®-1 KMY.
CURING TREATMENT
Generally not required but precautions should be taken for applications done directly under sunlight and windy condition.
CLEANING OF TOOLS
Clean all tools and application equipment with clean water immediately after use. Hardened or cured material can only be removed mechanically.
FAQ
Sikalastic®-1 KMY, a one component fiber reinforced, flexible cementitious waterproofing is the recommended product for swimming pool waterproofing before tiles for both wall and floor.
Due to the porosity of the gypsum surface, Sika recommends a primer coat before the application of cementitious waterproofing. Sika® Primer-11 WMY is required prior to the application of SikaTop® Seal-107 (MY), SikaTop® Seal-109 MY and Sikalastic®-1 KMY.