Tackling tiling projects over substrates prone to movement, within immersed areas like swimming pools, or directly over underfloor heating systems demands a specific type of adhesive. RLA Flex Pro delivers the required high flexibility and bond strength. It ensures tiles remain secure, even when conditions challenge rigid systems, providing a lasting finish in demanding internal and external environments.

Why this product exists

RLA Flex Pro is a high-performance, cement-based tile adhesive engineered for applications where flexibility and robust adhesion are critical. It allows tilers to confidently fix ceramic, porcelain, and natural stone tiles to floors and walls. This formulation specifically addresses the challenges of dynamic environments, accommodating the movement that often leads to tile failure in less adaptable adhesives.

The numbers that matter

Tensile Adhesion Strength of over 1.5 MPa ensures tiles remain firmly fixed. This robust bond strength resists shear and pull-off forces, even in high-traffic or externally exposed areas. An open time of 20-30 minutes provides a practical window for efficient tile placement, particularly useful for larger format tiles or complex layouts.

Critical for wall tiling and facades, a “no vertical slip” rating holds tiles in position immediately after placement, preventing sag and ensuring alignment during installation. Furthermore, foot traffic is permissible in 24 hours, allowing for quicker project progression and enabling subsequent trades to access the area sooner.

What it's like to use

RLA Flex Pro mixes easily with clean water to a smooth, lump-free consistency using a mechanical mixer. After a brief 5-minute stand time, the adhesive is ready to apply with a notched trowel. Optimal coverage requires ensuring full adhesive contact to the tile back, pressing tiles firmly into the adhesive bed with a twisting motion. Prompt cleaning of excess adhesive from tile surfaces and grout joints during application simplifies cleanup. For porous substrates, RLA Universal Primer prepares the surface, ensuring consistent bond and performance.

Where this product excels

  • Tiling: Ideal for fixing large format porcelain or natural stone on floors and walls, particularly where substrate movement is anticipated. This includes busy commercial floors or residential areas with fluctuating temperatures.
  • Wet Areas & Swimming Pools: The water-resistant formulation and high bond strength make it suitable for permanently immersed conditions like swimming pools, as well as bathroom floors and shower recesses, preventing water ingress and tile delamination.
  • Underfloor Heating Systems: Designed to withstand the thermal expansion and contraction associated with heated slabs, maintaining a secure bond and preventing tile cracking or lifting over time.
  • External Applications: Performs reliably on external patios, balconies, and facades where exposure to weather and temperature extremes demands a flexible and durable adhesive.

Don't use this when

  • Not for: Direct application over timber. Timber substrates require specific adhesives or preparation not compatible with RLA Flex Pro.
  • Not for: Use on metal or plastic substrates. This adhesive is not formulated for adhesion to non-porous metal or plastic surfaces.
  • Not for: Use as a final waterproofing membrane. RLA Flex Pro is a tile adhesive, not a primary waterproofing barrier.

This product's VOC content is below detectable limits, conforming to SCAQMD Rule 1168 standards.

RLA Flex Pro vs. RLA Polymastic Primer: Choosing the Right Flexible Tile Adhesive

Both RLA Flex Pro and RLA Polymastic Primer are high-performance, flexible tile adhesives from the RLA family, but they serve different project needs. RLA Flex Pro is a cement-based adhesive designed for demanding internal and external tiling applications, offering excellent adhesion and flexibility over movement-prone substrates, including immersed areas like swimming pools and over underfloor heating systems. In contrast, RLA Polymastic is a polymer-modified cement-based adhesive known for its superior bond strength and flexibility, particularly for large format tiles and challenging substrates that require enhanced adhesion, such as some external and commercial projects. Choose RLA Flex Pro when your project demands a high-flexibility cementitious adhesive for general internal and external areas, wet areas, or underfloor heating. Opt for RLA Polymastic for those critical applications needing the highest possible bond strength and maximum flexibility for oversized tiles or extremely demanding conditions.