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  • ABM Tiling Limited

Case Study: Efflorescence Eradication in Pool Tiling - The Art of Seamless Solutions

At ABM Tiling, we pride ourselves on being experts in the field of pool waterproofing and tiling. One of the many challenges we've tackled in our journey is the persistent issue of efflorescence in pools and how to eradicate it from any of the pools we work on using tried and tested solutions. Efflorescence is a concern that plagues many pool owners and contractors, and through our extensive experience, we've developed a comprehensive understanding of its causes, prevention, and mitigation.

We hope that this case study will help others to avoid the many issues that can cause this problem.

Pool wall with efflorescence coming through the grout joints

The Enigma of Efflorescence

Efflorescence, the bane of pool owners and builders alike, is a phenomenon that emerges in materials containing "free calcium." These materials include cement, gypsum-based products, rendering products, tile adhesives, and grouts. Its formation is influenced by environmental conditions, with an ideal temperature of 7°C and an atmospheric humidity of 80% providing the perfect breeding ground.

Identifying the Culprits

Efflorescence is primarily caused by:

  1. Choice of Products: The materials used in construction, such as adhesives and grouts, can contain free calcium, making them potential sources of efflorescence.

  2. Inadequate Drying and Curing: Rushed drying and curing times, especially in challenging environmental conditions, can exacerbate efflorescence problems.

Efflorescence Prevention Strategies

To ensure a pristine pool tiling job, we employ the following strategies:

  1. Optimal Working Conditions: Whenever possible, we schedule our work during warm, dry periods, minimizing the risk of efflorescence formation.

  2. Concrete Shell Protection: We ensure the pool's concrete shell has a damp-proof membrane (DPM) between it and the surrounding earth to prevent water ingress, which can lead to efflorescence and structural issues.

  3. Strict Drying and Curing: We meticulously adhere to recommended drying and curing periods, especially during colder seasons, to ensure a stable foundation for tiling.

  4. Adequate Ventilation: Proper pool ventilation, including the use of fans during colder months, prevents the stagnation of air, reducing the likelihood of efflorescence.

  5. Surface Moisture Testing: We test surfaces for moisture levels before applying subsequent layers, using methods like "Hygrohood" or moisture meters for accuracy.

Tanking and Efflorescence

Efflorescence can even occur through tanking during drying. If it happens, we ensure the efflorescence is removed. Correctly applied tanking seals free calcium particles behind it, ensuring any remaining efflorescence stems from adhesive and grout layers.

Adhesive and Grout Strategies

We take a proactive approach with adhesives and grouts:

  • High-Quality Surfaces: We ensure the pool's surface is planar, allowing us to use a thin bed of adhesive, reducing the quantity of free calcium in the system.

  • Full Bed of Adhesive: A full bed of adhesive minimizes air pockets, crucial for preventing water infiltration and free calcium mobilization.

  • Avoid Slow-Set Adhesives: Slow-set adhesives with Portland cement are more likely to cause efflorescence; we prefer rapid-setting adhesives.

  • Correct Mixing: We use paddle mixers that don't introduce air into the adhesive, making it denser and less permeable to water and free calcium.

  • Epoxy Adhesives and Grouts: Epoxy adhesives and grouts eliminate free calcium and capillary action, offering superior efflorescence resistance.

  • Expansion Joints: We maintain a minimum 6mm gap between tiles in internal corners, filled with suitable expansion joint filler, to reduce grout cracking.

The Water Factor

The purity of pool water can influence efflorescence. Highly purified water may draw out free calcium more vigorously through capillary action, potentially exacerbating efflorescence. The region's water source can also play a role, with harder waters being less prone to efflorescence than softer waters.


Efflorescence may pose challenges in pool tiling, but at ABM Tiling, we've honed our expertise to ensure its prevention and management. Our commitment to adhering to best practices, using high-quality materials, and employing advanced techniques sets us apart as trusted experts in the field. When you choose ABM Tiling, you choose excellence, quality, and a pool that stands the test of time.

A pool constructed perfectly without efflorecence

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