Kerakoll Bioflex S1 Grey Highly Flexible Polymer-Modified Tile Adhesive – 20 kg

Kerakoll Bioflex S1 Grey is a premium, eco-friendly deformable mineral tile adhesive engineered for high-strength fixing of porcelain stoneware, large-format vitrified tiles, and non-sensitive natural stone. Certified as a Class C2TE S1 adhesive, its advanced polymer-modified matrix provides exceptional flexibility, crack-bridging performance, and sheer bond strength.

Formulated with natural minerals and low-carbon cementitious binders, Bioflex S1 Grey absorbs heavy structural loads, subfloor deflections, and thermal movements. It is highly recommended for challenging architectural applications, including high-traffic commercial floors, external balconies, and substrates with embedded radiant underfloor heating.

Key Features & Benefits

• S1 Deformable Flexibility: High elastic properties easily absorb structural settle, subfloor vibrations, contraction, and expansion forces to prevent tile cracking or delamination.

• Extended Open Time & No Vertical Slip (T): Gives installers an optimized open working window ($\ge$ 30 minutes) to adjust tiles precisely, while ensuring zero vertical sag on walls.

• Universal Substrate Bonding: Adheres effortlessly to standard cement screeds, concrete blocks, old tile-on-tile floors, gypsum boards, and timber substrates.

• Eco-Friendly Mineral Base: Developed with active natural minerals to achieve exceptionally low volatile organic compound (VOC) emissions, contributing to safe indoor air quality.

• Cost-Effective S1 Performance: Delivers the exact same advanced structural flexibility as Bioflex S1 White, making it the perfect budget-friendly solution for non-translucent tiles and dark stone materials.

Specifications

• Brand: Kerakoll

• Product Line: Bioflex S1 (Grey)

• Packaging Size: 20 kg Bag

• Adhesive Classification: Class C2TE S1 (Deformable Cementitious Adhesive)

• Maximum Bed Thickness: Up to 15 mm

• Water Mixing Ratio: $\approx$ 5.5 to 6.0 Litres per 20 kg bag

• Coverage/Yield: $\approx$ 1.2 to 1.5 kg/$m^2$ per mm of bed depth (covers roughly 45–55 sq. ft. per bag using standard notched trowels)

• Optimal Environments: Internal and external walls and floors, balconies, terraces, swimming pools, high-traffic commercial zones, and underfloor heating setups.

How to Use for Best Results

1. Substrate Preparation: Substrates must be compact, fully cured, completely structural sound, and clear of oil, old adhesive residues, laitance, or loose dust particles.

2. Mixing: Pour clean water into a mixing bucket and slowly stir in the Bioflex S1 Grey powder. Mix continuously with a low-speed mechanical mixer ($\approx$ 400 rpm) until a homogeneous, lump-free paste is achieved. Let the mix rest for 3 to 5 minutes, then stir briefly again.

3. Application Technique: Comb the mixed paste onto the substrate surface utilizing an appropriately sized notched trowel. Apply only enough material that can be comfortably tiled within the adhesive's active open time window.

4. Tile Embedding: Press the tile firmly into the wet mortar ridges using a slight twisting motion, or tap down with a rubber mallet to guarantee absolute transfer. For large format stoneware panels (larger than 60x60 cm), the double-spreading (back-buttering) method is highly recommended to eliminate hollow air voids underneath.

Note: Because this product has a dark grey cement base, it is not recommended for translucent glass mosaics, light-colored translucent marbles, or white natural stones where color bleed-through or shading might be visible. Use Bioflex S1 White for those delicate materials.