Installation
These instructions for laying are drawn up for all natural stones and are therefore not in detail. We also have technical data sheets for each material and advise you to download them on the specific product sheet.
- Prior to the installation
- Preparation
- Installation
- Installation in combination with underfloor heating
- Joints
- After the installation
1. Prior to the installation
After delivery on site the tiles should immediately be placed inside or at least covered to protect them from wind, rain and frost. Certain types of natural stone (e.g. travertines) cannot be transported when it’s freezing. Slates, quartzites and sandstones have to be carefully inspected and cleaned before installation: all mud traces and/or surface scalings are to be removed. Should there be damaged or broken tiles then the supplier should be informed before installation. These slightly damaged tiles are to be used as much as possible against the walls and for cutting. The area where the tiles are to be installed must always be protected from rain, frost and draught; floor or walls must not be damp.
2. Preparation
The concrete floor/screed must have dried out for a minimum period of 28 days. Do not make the tiles wet before installing! To avoid penetration of dampness via the concrete structure underneath, a double layer of polyethylene plastic is placed between the concrete slab and concrete floor/screed; a single plastic layer underneath the concrete slab is insufficient. The edges of the double sheet must be raised at the level of the joint between floor and skirting board and cut off there. When the area to be tiled is 50 m² or when the length is more than 10 m, an expansion joint has to be installed vertically through the concrete floor/screed and adhesive by using expandable polystyrene or a similar product. This procedure is the same for wall tiles.
The stone material and the stone finish should be selected to suit the area it is being applied for. In order to prevent the tiles from being scratched or worn away, it is recommended to put a suitable floormat between the internal flooring and the external areas: sandgrains on shoesoles can very easily scratch the tiles.
3. Installation
General procedures of good workmanship should be followed when laying the tiles. Please be advised that some natural stone materials can have size tolerances in thickness, size and squareness depending upon the size of the tiles. Always contact our offices should you require more information about this or consult our technical data sheets. Before the fixing, the installer, the client and/or architect have to check if the tiles (in dry condition) match the sample. Before installing, carefully mix the tiles to achieve a harmonious appearance of colours and shades. Important: “Installation is acceptance”: this means that AFTER installation no complaints will be accepted except for hidden faults.
With white marbles, slates and quartzites the back of the tiles are to be covered with BELTRAMIX mixed with white sand and white cement minimum 24 hrs before the installation (ratio depends on percentage of resin present - cfr. the supplier’s instructions). The flooring should be installed with BELTRAFLEX (adhesive – maximum 1.5 cm thick) or a white based cement mortar (maximum 1.5 to 3 cm thick) on the concrete floor/ screed. Drying time floor: 1 week/cm thickness + 1 extra week (e.g. concrete floor/screed is 7 cm = 8 weeks drying time). Double bonding is necessary; this means that both the back of the tiles and the concrete floor/screed are covered with BELTRAFLEX/adhesive. After laying do not spray the tiles with water. The joints must be left open for several days (a minimum of 14 days when the weather is damp) so that the moisture can evaporate through these joints.
4. Installation in combination with underfloor heating
it is recommended that the supplier’s instructions are strictly adhered to. Installation with BELTRAFLEX (adhesive - maximum thickness 1.5 cm) and calibrated tiles (when available) only on a dry concrete floor/screed. Drying time floor: 1 week/cm thickness + 1 extra week (e.g. concrete floor/screed is 7 cm = 8 weeks drying time). A rustproof metal reinforcement net (e.g. 50 / 50 / 2 mm - no chicken net) must be incorporated in the concrete floor/ screed. It is recommended to work with straight joints; irregularly sized tiles will also increase the risk of crack formation. Expansion joints have to be placed per area of 40 m² or per 8 lm. Against the walls an expansion joint also has to be installed by using expandable polystyrene or a similar product.
To summarize the installation procedure: A good thermal insulation is placed on top of the concrete floor/screed. On top of that a galvanised metal reinforcement net (see above). In between those a plastic (polyethylene) foil is laid. The heating pipes are placed above the insulation and covered by concrete floor/screed. Sometimes they are wholly or partly placed in the insulation. The composition of the base is normally 250 to 320 kg cement/m³. You can also use quick drying kinds of mortar. The thickness of the base is normally 75 mm. Before the installation of the floor, the heating has to be started up gradually. This can be done after a waiting period of a minimum of 28 days after the installation of the concrete floor/screed by increasing the heat by 5°C per 24 hrs. After the heating system has worked for a minimum of 3 to 7 days on maximum temperature, the temperature has to be decreased gradually until the normal starting temperature has been reached again. After having waited an extra day the natural stone can be installed.
5. Joints
The thickness of the joints for internal use is 3 to 4 mm for tiles 40/40 cm and 5 to 6 mm for tiles 60/60. The grout is BELTRAJOINT. With slates, quartzites, sandstones and also antiqued limestones (e.g. Roman pavement in rustico finish) and external flooring, the thickness of the joints will be wider (0,5 to 1 cm: always consult the technical data sheets).
6. After the installation
During the grouting it is important to clean the tiles in order to avoid a cement film. Do not hinder the evaporation through the stone when the tiles are drying: avoid covering the tiles with sheets, carpets, carton etc. Avoid covering the tiles with a temporary cover to protect them for further works because this can damage the tiles. Only when absolutely necessary PROCELL covering can be used to cover and protect the tiles. The acceptance of a natural stone surface can never be done against the light. The inspection is carried out on a man’s height and with the naked eye. Colour differences can only be judged when the tiles are completely dry.
Do you experience specific problems which are not mentioned on the technical datasheet ? Please use our forum ! A team of specialists are ready to answer your question as soon as possible.