The installation substrate should be dimensionally stable, having completed any possible drying shrinkage. It should be properly plumb or level and not have any defects in flatness greater than 2 mm., checked using a 2-metre straightedge. It should be completely free of dust, grease or any other substances that could hinder adhesion.
The substrate should be checked to make sure that it has the proper consistency, with any brittle (crumbly) or easily detachable parts being removed. These defects as well as any deviations in flatness should then be corrected. All substrates, except for floating screeds and when separating layers have been used, should always be firmly bonded to their corresponding bearing substrate. For the treatment of special substrates (non-absorbent, deformable, gypsum, etc.), check with the Technical Service Department (see details at the end of this catalogue).
With the traditional way of laying ceramic tiles, fresh mortar was used. Nevertheless, Gres Cid recommends the use of professional adhesives that ensure higher levels of tiling performance.
We recommend the use of the thin-bed method with H40 FLEX® (C2 as per EN 12004) by KERAKOLL, MAPESET® (ZA as per EN 12004) or KERABOND® (C1 as per EN 12004) by MAPEI. A notched trowel should be used with a notch size suitable for the tile format being installed and the substrate’s surface texture (5-10 mm).
Tiles should then be placed on the fresh adhesive, making sure that a surface film has not formed. Firmly press them into the adhesive using a back-and-forth motion in order to achieve the greatest amount of coverage on the underside of tiles. Any possible adjustments to tiles once they have been embedded in the adhesive should be made within the adhesive’s adjustment time. In addition, the adhesive’s corresponding “ready for traffic” time should be observed before exposing the floor to traffic.
On outdoor surfaces that are subject to water, the substrate must have a slope of at least 1% so that water can drain away. It is crucial to make sure that the tiles are firmly fixed in place with no unbonded areas. To ensure this, the floating and buttering method must be used. With this technique, adhesive is applied to both the substrate (spreading a layer across the surface and passing a notched trowel across it) and the back of the tile (where a light coat of adhesive should be applied using the smooth part of the trowel).
For outdoor environments, you must always use C2 cement-based resinous adhesives in accordance with EN 12004. You can use an adhesive called H40 FLOTEX® (rated C2 according to EN 12004) by KERAKOLL or KERAFLEX® (rated C2 according to EN 12004) by MAPEI. By spreading it across the substrate using a deep notched trowel (with 8-15mm teeth), the tiles will remain firmly bonded with no hollows.
Tiles may also be embedded by covering them with a clean, hard-rubber block and tapping it with a rubber mallet.
In any event, some recently laid pieces should be prised up on a regular basis to ensure that proper coverage has been achieved.
It is vital that tiles not be installed touching each other, leaving the amount of space between them as per the regulations or guidelines currently in force. The use of the proper wedges or spacers will help to make sure that tiles are well-aligned both vertically and horizontally.
On outdoor paving or floors that may be subject to water, the substrate must be sloped at an angle of at least 1% so that water runs off it.
For grouting installation joints, use FUGABELLA® by KERAKOLL, or KERACOLOR® or ULTRACOLOR® (CG2 as per EN 13888) by MAPEI, products in the range of professional grouting mortars that are suitable for use with all types of ceramic tiles. Different grout mortars are available to grout joint widths ranging from 0 to 20 mm. Grout mortar should be applied with a hard-rubber straight-edged trowel, in a repeated diagonal motion across the joints. Excess grout can be scooped up with the selfsame trowel.
We also emphasise the importance of using the proper amount of water in the mix (as stated on the package) and not using or adding water to and reworking mixed grout once it has begun to set.
It is important to perform cleaning within the manufacturer’s recommended times. In any event, climatic conditions should be taken into account to lengthen or shorten the bonding material’s drying times as required.
Use a fine-textured hard sponge dipped and rinsed in clean water. Do not use scrub brushes or scouring pads that may alter tile colour or steel trowel that may scratch the tiles’ glaze covering. For optimal cleaning, use KERANET® by MAPEI or DELTA PLUS by KERAKOLL, observing the drying time for the grouting material.
Any existing expansion joints, such as structural or contraction joints, should be left in place. Elastic expansion joints should be rendered in order to separate the different tiled sections and keep them apart from other elements. This will avoid the build-up of stresses due to possible expansions and differential deformations once the tiles have been installed. In addition to intermediate dividing joints, perimeter joints should be rendered wherever the coverings come into contact with any other fixed point, e.g., structural elements such as columns or beams, connections with downspouts, uprights or bracing members, connections with door/window frames, etc. These joints should be left empty (or filled with a suitable compressible material) along their entire width and height, and may be finished either during tile installation (with pre-formed PVC profiles) or afterwards using highly elastic joint sealant SIGIBUILD® by KERAKOLL or MAPESIL AC® (Class A as per USA TTS-001543A) by MAPEI. In any event, the minimum recommended width for expansion joints is 8 mm.
Bibliography: “Guide to Ceramic Tiles” del Instituto Valenciano de la Edificación. Colegio Oficial de Arquitectos de la Comunidad Valenciana. Consellería de Obras Públicas y Transportes de la Generalitat Valenciana.
The information contained herein is intended for the purpose of orientation. Given the multiple variables and situations that may come into play in ceramic tile installation, we recommend that you contact, for any doubts or situations not covered in this catalogue, Gres Cid’s Technical Service at +00 34 902 38 11 55, Kerakoll’s Worldwide Global Service at +00 34 902 32 55 55 or MAPEI’s Technical Service Department at +00 34 93 343 50 50.