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When the tile installation demands superior strength, flexibility, and enduring performance, even in continuous water immersion or over early-age concrete, ARDEX X 18 delivers. This advanced adhesive provides the robust bond and movement tolerance needed to secure large format tiles and natural stone in challenging internal and external environments, eliminating costly callbacks and ensuring long-term stability. Trade professionals choose this product to confidently install without compromise.
ARDEX X 18 is engineered for the most demanding tiling scenarios. It combines superior polymer fortification with fibre reinforcement, creating an adhesive that goes beyond standard cement-based formulations. This design provides exceptional tensile strength, flexibility, and non-slump characteristics, crucial for securing large or heavy tiles in high-traffic areas, external exposure, or continuously immersed environments like commercial swimming pools. Its formulation also allows for reliable application over early-age concrete, addressing a common job site challenge where minor substrate movement is anticipated.
ARDEX X 18 holds a C2 TE S1 classification, a critical indicator of its high performance. C2 signifies improved cementitious adhesive, offering superior bond strength compared to conventional adhesives. The T denotes its non-slump properties, essential for large format and heavy tiles on walls, preventing slippage during installation. An E indicates an extended open time of 30 minutes, allowing for more efficient placement and adjustment of tiles without premature skinning. Lastly, S1 flexibility means it can accommodate minor substrate movement, crucial for external applications, over early-age concrete (minimum 7 days old), or in areas with temperature fluctuations.
Its tensile adhesion strength of ≥1.0 MPa, maintained after water immersion, heat ageing, and freeze-thaw cycles, directly translates to exceptional durability. This high performance ensures the bond holds firm in conditions from external patios exposed to harsh weather to commercial swimming pools under continuous water load, significantly reducing the risk of tile failure or lifting.
ARDEX X 18 offers excellent workability. It mixes with 5-6 litres of clean water per 20kg bag to a smooth, creamy consistency, with a pot life of approximately 3 hours. The 30-minute open time allows for precise tile placement, and the 30-minute adjustment time provides flexibility for alignment, reducing rework. For enhanced resilience to movement, such as on heated floors, or for even greater performance in swimming pools, it can be mixed with ARDEX E90 in place of some water. Always ensure tools are cleaned with water immediately after use, before the adhesive sets.
ARDEX X 18 integrates seamlessly into comprehensive tiling systems. For wet areas, it provides a reliable bond over ARDEX liquid applied undertile waterproofing membranes once cured. On porous substrates, priming with Ardex Multiprime is recommended to optimise adhesion. Once the tile bed is sufficiently firm (typically 24 hours at 23ºC), joints should be grouted with an appropriate ARDEX grout. Always ensure movement joints are installed in accordance with Australian Standard AS 3958, using an approved movement-joint sealant rather than grout.
Unlike standard cement-based tile adhesives such as ARDEX X 17, ARDEX X 18 is a superior polymer-fortified and fibre-reinforced formulation. While ARDEX X 17 is an excellent C2S1 adhesive for general-purpose internal and external applications, ARDEX X 18 offers enhanced strength, superior flexibility (S1), and non-slump properties due to its advanced composition. Choose ARDEX X 18 for the most robust applications, including continuous water immersion in swimming pools, over early-age concrete, or for very large and heavy tiles where maximum performance and durability are critical. For less demanding, general-purpose C2S1 tiling tasks where extreme conditions are not present, ARDEX X 17 remains a highly effective and economical choice.
Yes, ARDEX X 18 is formulated for internal and external use in swimming pools and wet areas. It maintains a strong bond, with ≥1.0 MPa tensile adhesion after water immersion and freeze-thaw cycles, preventing common failures.
The C2 TE S1 classification confirms ARDEX X 18 as an improved, cementitious adhesive (C2) with extended open time (E) and no vertical slip (T), plus S1 for flexibility. This allows it to handle minor substrate movement, reducing the risk of tile cracking or delamination.
ARDEX X 18 is not for direct use over substrates subject to shrinkage and other movement, such as untreated timber. For timber floors, a Ceramic Tile Underlay (CTU) of at least 6mm is required over plywood or particleboard, fixed per manufacturer instructions and AS 3958.
This adhesive is suitable for fully vitrified, ceramic, porcelain, and mosaic tiles. It can also be used for natural stones, with the important exception of moisture-sensitive types, which require a specific ARDEX Natural Stone System.
ARDEX X 18 offers a 30-minute open time and a 30-minute adjustment time, with a pot life of approximately 3 hours. This extended window allows for efficient setting of tiles over larger areas, reducing rework and ensuring proper placement.
| Application | Key benefit | Primary trades |
|---|---|---|
| Swimming pools and permanently wet areas | Delivers durable, waterproof adhesion with ≥1.0 MPa tensile strength after water immersion and freeze-thaw, preventing critical failures. | Tilers, Waterproofers, Builders |
| External wall and floor tiling | Withstands environmental extremes, maintaining ≥1.0 MPa tensile adhesion after heat and freeze-thaw cycles, ensuring long-term stability. | Tilers, Landscapers, General builders |
| Large format and heavy tiles | Non-slump properties and fibre reinforcement prevent tile drop and provide strong support, crucial for achieving level, uniform installations. | Tilers |
| Green Building Council of Australia Green Star projects | Meets Green Star requirements for ceramic tile adhesives, offering confidence for specification and compliance on sustainable projects. | Architects, Specifiers, Green builders |
| Over early-age concrete, screeds, and render | Flexible formulation accommodates minor substrate movement, reducing the risk of cracking in newly constructed surfaces (concrete min. 7 days old). | Tilers, Concreters, Builders |
| Internal residential and commercial spaces | Extended 30-minute open time and excellent workability allow for efficient, precise placement across diverse internal applications, from bathrooms to showrooms. | Tilers, Renovators, Interior fit-out teams |
Ensure your substrate is structurally sound, clean, dry, and free from any contaminants like dust, oil, or curing agents. All preparation must comply with Australian Standard AS 3958. Prime porous surfaces with ARDEX Multiprime.
Add a 20kg bag of Ardex X 18 powder to 5-6 litres of clean water in a container. Mix with a mechanical stirrer for at least 2 minutes until a lump-free, creamy mortar is achieved. Let it stand for 5 minutes, then remix for a final 2 minutes.
Apply the adhesive to the substrate with a notched trowel suitable for the tile size. Spread only enough adhesive that can be tiled within the 30-minute open time. For large format tiles (>400mm) or tiles with ribbed backs, also butter the back of the tile to ensure 100% coverage and eliminate voids.
Press tiles firmly into the mortar bed with a sliding motion at a right angle to the notches. Periodically lift a tile to confirm full coverage has been achieved.
Signal Word: Danger
Wear protective gloves (e.g., elbow-length PVC, neoprene, nitrile), protective clothing (overalls, PVC apron), safety glasses with side shields or chemical goggles, and a face shield. For dust exposure, use an approved dust respirator (Type P1/N95).
Use only outdoors or in a well-ventilated area. Avoid breathing dust or fumes. Prevent dust concentration in hollows and sumps.
Store locked up in original, securely sealed containers in a cool, dry area, protected from environmental extremes. Keep away from incompatible materials such as strong acids, oxidising agents, copper, and aluminium alloys. Dispose of contents and container to an authorised hazardous or special waste collection point according to local regulations. Avoid contamination of drains or waterways.
Proper surface preparation is crucial for achieving a durable bond and preventing tile failure. Follow these guidelines for specific substrates before applying ARDEX X 18.
Surface prep: Concrete must be at least 7 days old and 20 MPa. Remove sealers or curing compounds. Mechanically roughen steel trowel finished or dense concrete (>35 MPa) to remove laitance and create a key. Ensure the surface is true, level, and pitched to drains where required.
Primer: Prime porous concrete with ARDEX Multiprime.
Surface prep: Finish new renders and screeds with a wood float to achieve the required regularity. Allow at least 24 hours to cure for bonded screeds, or 7 days for unbonded screeds, before tiling.
Primer: Prime porous renders and screeds with ARDEX Multiprime.
Surface prep: Boards must be firmly and rigidly fixed as per the manufacturer's instructions. Ensure they can adequately support the tile bed weight.
Primer: Priming is recommended for fibre-cement sheet. Plasterboard typically does not require priming unless jointing compound has been used.
Surface prep: Existing tiles must be sound, clean, firm, and stable. Roughen the surface mechanically to remove at least 80% of the glaze. Clean off all contamination and dust before tiling. Not recommended for immersed applications.
Primer: Prime with ARDEX Multiprime or ARDEX P9.
| Property | Value |
|---|---|
| Colour | White or Grey |
| Mixing Ratio | 5 - 6 litres water per 20kg powder |
| Classification | C2 TE S1 |
| Open Time | 30 mins |
| Adjustment Time | 30 mins |
| Pot Life | 3 hours |
| Grouting Time | 24 hours |
| Sagging | None |
| Underfloor Heating | Yes |
| Tensile Adhesion 28 Days Dry | ≥1.0 MPa |
| Tensile Adhesion Water Immersion | ≥1.0 MPa |
| Tensile Adhesion Heat | ≥1.0 MPa |
| Tensile Adhesion Freeze Thaw | ≥1.0 MPa |
Here are some common examples on where Ardex X 18 Tile Adhesive used by our customers.
