SikaCeram® FLX 420

SikaCeram® FLX 420 meets the requirements of EN 12004-1 for class C2T.

Powder mixture with elastifying polymers. Does not contain any asbestos or other mineral fibres. No injurious silica dust during the application.

12 months from date of production

Store in undamaged, unopened, original sealed packaging in dry conditions at temperatures between +5°C and +35°C. Protect from direct sunlight, heat and moisture.

In normal conditions on cement based substrate, no primer is required. However, for very high absorbent substrates (e.g. drywalls) or non-absorbent substrates, please contact Sika Technical Service for recommendation.

-30°C min. / +80°C max.

Max. 10 mm

+5°C min. / +35°C max.

6.0 to 6.25 L of water per 25 kg bag

~3 min. (Slake time)

~1 h (at +23°C)

~30 min. (at +23°C)

Values determined in laboratory conditions: +23 °C ± 2 °C, R.H. 50 % ± 5 %. Higher temperatures will reduce the indicated waiting times, lower temperatures will increase the indicated waiting time.

Powder consumption and coverage depends on the surface profile and roughness of the substrate, size and reverse profile of the tiles and the placing technique (simple placing "floating" or back to back “buttering-floating”).
As a guide for solid bed application:
For 1 mm thickness over 1 m² area approximately 1.2 kg of powder is required.

This figure is theoretical and does not allow for any additional material due to surface porosity, surface profile, variations in level, wastage or any other variations. Apply product to a test area to calculate the exact consumption for the specific substrate conditions and proposed application equipment. Above consumption indications refer to the installation of slightly profiled, non-vitrified or vitrified tiles on flat substrate e.g. render or cement screed.
For small sized tiles (side ≤30 cm), use small squared notch size trowel (4 - 6 mm) and progressively increas for medium tiles (side ≤45 cm, trowel 6 - 8 mm) or large tiles (side ≤60 cm, trowel 8 - 10 mm).

Select the most appropriate equipment required for the project:
Substrate preparation equipment:

• Grinding equipment
• Abrading equipment
• Power washing equipment
• Sandblasting equipment

Mixing equipment:

• Low speed electric single or double paddle mixer
• (300–400 rpm) with a spiral mixing paddle.

Application equipment:

• Notched trowel, various sizes

Minimum age of the substrate:

• SikaScreed® or SikaLevel® range – 3 days
• Cement screed - 28 days

Note: The screed drying time is subject to the screed thickness and site conditions. For applications before 28d please contact Sikas Technical Service Department. Newly applied cement screeds must not have a residual moisture content over 4%, anhydrite and/or gypsum-based screeds not more than 0.5% (measured with a CM meter).

• Cementitious substrates must be sufficiently cured and dried.
• All substrates must be structurally sound, able to support the weight of the new tiling and provide a firm and securely fixed background.
• The substrate must be flat, tight and free from easily removable parts, non- deformable and correctly aged.
• Substrates must be clean, dry, free of any loose or friable particles, contaminants such as dust, dirt, oil, wax polish, grease, cement laitance or efflorescence.
• Use adequate mechanical preparation techniques to remove from the substrate, all traces of any materials that could reduce the product's adhesion to the substrate.
• The substrate must be plumb and flush in accordance with BS 5385. Plaster substrates must be approved by the plaster manufacturer for fixing ceramic tiles and must be suitable for the intended area of use.
• Smooth surfaces must be lightly roughened to improve adhesion.
• To confirm adequate surface preparation and adhesion, carry out a small trial before full application.
• For larger and thicker areas of substrate re-profiling, use suitable mortars from the Sika MonoTop® or SikaEmaco® range. Level concrete floors with Sikafloor ® 500 range screeds or Sikafloor® Level range.
• For any repairs of the substrate materials of SikaEmaco®, SikaRep® or Sika MonoTop® range should be used, applied at least 24 hours before laying the ceramic tiles.
• Identify cracks in the substrate and seal appropriately with Sikadur® epoxy resins.
• For applications in hot climates / environments, or on absorbent substrates, thoroughly pre-dampen (saturate) the substrate before product application. Avoid any ponding / standing water on the substrate. Surface must not be damp to touch.
• For tiling in constantly damp or wet rooms, a suitable Sika® waterproofing product / systems must be applied to the substrate before tiling.
  Prime very absorbent cement based substrates and aerated concrete with SikaCeram® P 302, diluted 1:1 with water, anhydrite and/or gypsum based floated screeds as well as gypsum based substrates inside of buildings with undiluted SikaCeram® P 302. Allow the primer to dry.

• Mix a bag with the necessary, above mentioned, amount of water, using an electric blender with a suitable mixing spiral at low speed, in a clean bucket, to obtain a smooth paste free of lumps.
• Use a blender at 500 rpm maximum; do not mix at faster rate because of mechanical strength decay of the cured product.
• Allow a maturing time (slake time) of approx. 3 minutes for SikaCeram® FLX 420 in the mixing container, then remix briefly prior to application.
• Always start with minimum recommended quantity of water (water/powder ratio), only if required, gradually add water to desired consistency. Do not exceed maximum allowed limit of water per bag weight.
• The obtained mix results should be very creamy, easily spreadable and thixotropic.
• Do not mix more material than can be used within 60 minutes.

SikaCeram® FLX 420 is applied using notched trowel. The amount of product should be enough to ensure complete wetting of the tiles rear. Tiling has to be carried out on fresh glue, exerting an adequate pressure to ensure contact with the adhesive, and thus the perfect bonding.

In case a surface film is formed on the adhesive, it is necessary to wipe the trowel on the adhesive layer previously applied. Avoid wetting already applied adhesive with water, as it may negatively affect its properties.
Note: For tiles > 900 cm² (30 x 30 cm), the double spreading ("buttering") technique is always recommended.

Adhesive application:

• Apply a thin scratch coat to the substrate with the smooth edge of the trowel.
• Comb mortar onto the fresh scratch coat with a notched trowel.
• Apply sufficient adhesive to the prepared fixing surfaces with the notched trowel to the required bed thickness, in one direction.
• Place the tiles in the adhesive bed with a twist and slide motion and adjust to correct position.
• Adjust the tiles if required.
• Clean off surplus adhesive from tile face and between tile joints before the adhesive has dried.

Clean all tools and application equipment with water immediately after use. Hardened / cured material can only be removed mechanically.