Sikasil® WS-355 N is a high-performance neutral curing silicone sealant with a high movement capability and very good adhesion to porous and non-porous substrates, suitable for sealing facades, e.g. cladding of natural stone such as marble, granite, sandstone and quartzite. With these materials, no staining of the joint edges occurs, unlike with conventional silicone sealants. It has been developed as weatherseal specific on natural stone.
Features:
- Does not stain areas adjacent to the joint
- Meets requirements of ASTM C 920 for Type S, Grade NS, Class 50 (movement capability ± 50 %), ASTM C 1248
- Very good UV and weathering resistance
- Adheres well to natural stone, concrete, glass, metals, coated and painted metals, plastics and wood
Preparations:
- Surfaces must be clean, dry and free from grease, oil and dust. Surface treatment depends on the specific nature of the substrates and is crucial for a long lasting bond.
Applications:
- The optimum temperature for substrate and sealant is between 15 °C and 25 °C.
- Sikasil® WS-355 N can be processed with manual, pneumatic or electric driven piston guns. Joints must be properly dimensioned.
- For optimum performance the joint width needs to be designed according to the movement capability of the sealant based on the actual expected movement. The minimum joint depth is 6 mm and a width / depth ratio of minimum 2 : 1 and maximum 4 : 1 must be respected. Joints deeper than 15 mm must be avoided.
- For backfilling, it is recommended to use closed cell, sealant compatible foam backer rods e.g. high resilience polyethylene foam rod. If joints are too shallow for backing material to be employed, we recommend using a polyethylene tape. This acts as a release film (bond breaker), allowing the joint to move and the silicone to stretch freely.
