Ardex X18 Tile Adhesive

Description

ARDEX X18 is a superior polymer-fortified, cement-based wall and floor tile adhesive formulated with mastic-type properties. It contains specially developed fibres that add strength to the tiled area, and is mixed with water to produce a mortar suitable for internal and external use in residential and commercial applications, including swimming pools. Manufactured by ARDEX Australia.

The combination of fibre reinforcement and a non-slump consistency is what separates it from a standard C1 adhesive: heavy and large-format tiles stay where they are placed on a wall rather than creeping down it, while the 30-minute open time and 30-minute adjustment window give enough working room to lay and true up a run before the mortar skins. Classified C2 TE S1 to ISO 13007. Also written ARDEX X 18.

Technical Specifications

Coverage Rates

Coverage depends on the notched trowel used, which in turn depends on tile size. AS 3958 Table 5.6.2.2 gives trowel-size guidance by nominal tile size. A 20 kg bag of ARDEX X18 yields approximately:

Coverage varies with substrate condition, tile type and application technique. Tiles with ribbed or keyed backs and large-format tiles need back-buttering, which increases consumption.

Where to Use

ARDEX X18 fixes fully vitrified and ceramic tiles, porcelain, mosaics and natural stones (excluding moisture-sensitive stones) to:

• Concrete, renders and screeds
• Fibre-cement sheet and plasterboard on walls
• Compressed fibre-cement sheet on floors
• ARDEX liquid-applied undertile waterproofing membranes
• Existing ceramic tiles in internal dry areas
• Ceramic tile underlay (CTU) over particleboard and plywood timber floors

How to Apply

1. Prepare the substrate – the surface must be clean, firm and free of dust, dirt, oil, grease, curing compounds and release agents, and strong enough to carry the weight of the tiles. Surfaces must be dry, with no residue or permanent damp. Prime porous substrates with ARDEX Multiprime. Early-age concrete must be at least 7 days old and no less than 20 MPa; smooth or dense concrete above 35 MPa must be mechanically roughened first.
2. Mix – add the powder to clean water in a large clean container while stirring vigorously, using 5 to 6 litres of water per 20 kg bag. Mix for at least 2 minutes to a lump-free mortar of thick creamy consistency, allow to stand for 5 minutes, then mix a second time for 2 minutes. Do not add additional water. Do not apply below 5 degrees C.
3. Comb out – select the trowel from the substrate, tile type and tile size, following AS 3958 Table 5.6.2.2. Spread only as much adhesive as can be tiled while the mortar is still wet.
4. Fix the tiles – press each tile firmly into the freshly combed bed and slide it at right angles to the notch pattern to achieve full contact. Tiles with ribbed or keyed backs, and large-format tiles measuring 400 mm or more in either direction, must also be back-buttered. Do not spot fix. Lift a tile occasionally to check there are no voids beneath it.
5. Clean and grout – remove surplus adhesive from the tile face and joints before it sets, and clean tools with water immediately after use. Grout once the bed is firm, usually 24 hours after fixing at 23 degrees C and 50% relative humidity. Allow longer for dense tiles, humid climates and low temperatures.

Important Notes

• Tiling must be carried out in accordance with Australian Standard AS 3958, including movement joints.
• Do not use over metal or similar substrates.
• Do not use over substrates subject to shrinkage or other movement, such as timber – ARDEX supplies other systems for these.
• Floor deflection must not exceed the joist span divided by 500 for tiles under 600 mm, or divided by 700 for larger tiles. Joist spans must comply with AS 1684.
• Ceramic tile underlay must be at least 6 mm thick and made for the purpose. Tiles under 100 mm edge length cannot be fixed by that method.
• When tiling over existing tiles in internal dry areas, remove at least 80% of the glaze mechanically and prime with ARDEX Multiprime or ARDEX P9. Tiling over existing tiles is not recommended in immersed applications.
• Dimensional instability in natural stone is often not visible and may need thermal and moisture stability testing before an adhesive recommendation can be warranted.
• Store in the original unopened packaging in a dry place; shelf life is 12 months at 23 degrees C and 50% relative humidity.

Frequently Asked Questions

How much ARDEX X18 do I need per square metre?

A 20 kg bag of ARDEX X18 covers approximately 11 square metres on walls using a 6 mm notched trowel, or approximately 7 square metres on floors using a 10 mm notched trowel. Coverage varies with substrate condition, tile type and application technique, so allow extra where the surface is uneven or where tiles are back-buttered.

How long can you adjust tiles after fixing with ARDEX X18?

ARDEX X18 has an open time of 30 minutes and an adjustment time of 30 minutes at 23 degrees C and 50% relative humidity. The pot life of the mixed mortar is approximately 3 hours under the same conditions. Site conditions change these figures, so only spread as much adhesive as can be tiled while the mortar is still wet.

Can ARDEX X18 be used in swimming pools and wet areas?

Yes. ARDEX X18 is formulated for internal and external residential and commercial applications including swimming pools. It can also be applied over ARDEX liquid-applied undertile waterproofing membranes, provided the membrane has been installed to instructions and is thoroughly dry before tiling. For improved resilience to movement in pools and heated floors, ARDEX X18 can be gauged with ARDEX E90 at 2.0 litres of E90 to 4.5 litres of cool clean water in place of the normal water addition.