ARDEX X77 - Flexible adhesive for low porosity tiles

Cement-based flexible tile adhesive with Microtec® technology for fixing low porosity tiles. Waterproof and highly deformable. No efflorescence. With fibres. High performance. Walls and floors. Interior and exterior. Complies with EN 12004 C2 TT EE S1.

Color ES
  • Gray
Packaging format
Tax excluded


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Flexible adhesive cement for low-porous materials with Microtec® technology for the installation of low-porous materials. Waterproof and highly deformable. No efflorescence. With fibres. High performance. Walls and floors. Interior and exterior. Complies with EN 12004 C2 TT EE S1.

Field of application:

Indoors and outdoors. Walls and floors.

Laying of:

  • - Ceramic, stoneware and porcelain tiles.
  • - Glass and porcelain mosaics.
  • - Concrete cut stone.
  • - Natural stone that is not very sensitive to humidity.

Laying of:

  • - Panels suitable for construction, e.g. plasterboard.
  • - Rigid foam and mineral fibre insulation boards.
  • - Rigid foam insulation boards with mortar coating on both sides, Wedi type.

Laying of tiles in swimming pools.

Laying of ceramic tiles on facades.

Laying tiles on concrete and masonry still in the shrinkage phase (at least 3 months old).

Laying of tiles on floors with underfloor heating.

Product description:

Composite powder based on cements, special additives, MICROTEC fibres and flexible synthetic materials. When mixed with water, a soft, paste-like adhesive mortar with high stability is obtained. The application time is approximately 3 hours. The mortar hardens by hydration and drying.

Preparation of the substrate:

The substrate, dry or wet, must be firm, able to bear weight, resistant, free of dust, dirt or separating elements.

Gypsum substrates, as well as porous or sanded floors, must be dry and a first coat of ARDEX P51 primer, diluted with water 1:3, must be applied.

Non-porous substrates made of metal, glass, varnish paints, etc., in interiors, must be pre-coated with ARDEX P82, synthetic resin.

In interiors, existing ceramic substrates must be pre-treated with either a first coat of ARDEX P82 or a thin coat of ARDEX X77. In exteriors, existing tiles should be primed with ARDEX P4 or a thin coat of ARDEX X77.

In areas of permanent humidity and outdoors, substrates should be treated beforehand with Ardex waterproofers.

Directions for use:

Pour clear water into a clean mixing bowl and mix a corresponding quantity of ARDEX X77 powder until a lump-free, flexible and stable mortar is obtained.

The mortar should be stirred again before application on the substrate to improve its elasticity.

Approximately 11 litres of water are required to mix 25 kg of ARDEX X77 powder.

The consistency of the mortar may vary slightly in each case, depending on the type, size and weight of the coatings to be applied.

ARDEX X77 powder is mixed with ARDEX E 90, diluted with water at a mixing ratio of 1:2, to obtain a special adhesive with high deformability and water-repellent characteristics.

The mixing ratio is approx:

25 kg ARDEX X77 powder

4.5 kg ARDEX E 90

9.0 litres of water

The ARDEX X77 mortar is applied to the substrate and combed with a notched trowel in such a way as to ensure adhesion of the tiles over their entire surface. The choice of trowel is determined by the type, size and back of the tiles.

In the case of heavily stressed surfaces, it is recommended to use the double bonding system for maximum adhesion.

Rough and uneven substrates can be levelled with ARDEX X77. Once the levelling layer has dried, tiling can be carried out.

Tile fixing surfaces should not be larger than the set application time allows, and should be laid on a damp, pasty bed.

Tiles can be corrected up to 30 minutes after laying.

For bonding insulation boards, the mortar is applied in strips. The surface of the tiles should be mechanically scraped if the tiles do not have open pores.

In case of doubt, carry out a preliminary test.

ARDEX X77 should be worked at temperatures above +5°C and below +30°C.

Higher temperatures shorten processing and laying times, lower temperatures lengthen them.


When laying tiles on building slabs, care must be taken to ensure that the tiles are fixed to the internal substrate so that the tile installation is distortion-resistant and stable.

We recommend the use of ARDEX waterproofing products for waterproofing.

Products from the ARDEX natural stone system are suitable for the stain-free installation of marble and other natural stone in interiors.

In spas, saunas and public swimming pools, the use of ARDEX WA or ARDEX EG8 is recommended, both as a bonding and grouting material.

When laying tiles on floors in the shrinking phase, the field dimensions must be limited by laying expansion joints.


Contains cement. Irritating to skin. Danger of serious damage to eyes. Keep out of reach of children. Dust must not be inhaled. Avoid contact with eyes and skin. In case of contact with eyes, rinse thoroughly with water and seek medical advice. During handling wear protective gloves and goggles, as well as face protection. If swallowed, consult a doctor immediately and show the label.

When set, the product is physiologically and ecologically harmless.

GISCODE ZP1 = product with chromate-poor cement content.

Technical data:

Mixing ratio:

Approx. 11 litres of water per 25 kg of powder which corresponds to approx. 1 vol. water per 2 1/4 vol. powder.

Density: Approx. 1.0 kg/litre.

Density of the mortar when fresh: Approx. 1.5 Kg/litre.


On smooth substrates:

Approx. 1.0 kg/m² with a 3x3x3 notched trowel.

Approx. 1.6 kg/m² with a 6x6x6 toothed trowel.

Approx. 2.2 kg/m² with 8x8x8 notched trowel

Working time (20°C): Approx. 3 hours.

Setting time (20°C): (open time) Approx. 60 min. (measured with fresh mortar).

Setting time (20°C): Approx. 15 -30 min.

Workability (20°C): After approx. 24 hours, grouting is possible.

Grouting of walls: After approx. 8 hours.

Tensile strength: 

For stoneware tiles, after 28 days.

Dry and wet: approx. 1,0 -2,0 N/mm2

In heat: approx. 1,0 -1,5 N /mm2

In freeze-thaw cycles: approx. 1,0 -1,5 N/mm2

Suitable for underfloor heating: Yes.

Packaging: 25 kg bags.

Storage: Approx. 12 months in a dry place in its original closed packaging.

Product Details

Indoor and outdoor
Single component
Floor and wall
Normative UNE
UNE 12004 C2 TT EE S1
UNE 12004 - Type
C - Cementitious adhesive
UNE 12004 - Adherence
C2 - High adhesion
UNE 12004 - Drying time
Normal drying
UNE 12004 - Slipping
TT - Minimum slip
UNE 12004 - Open time
EE - Double Extended Open Time
UNE 12004 - Deformability
S1 - Deformable
Drying time
Marked CE
Quality certificate
ISO 9001 - LLoyds Register Quality Assurance Limited


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