Internal or external flooring in marble, granite, slate, quartzite, terracotta or ceramic tiles.
The flooring can be bedded or bonded depending on the thickness of the recess.
The bedded floor installation method is applicable to tiles or slabs’ thickness of 15mm, 20mm or more. It requires 4 to 5cm recess for bedding mortar. The reference document that regulates this installation method in France is the Unified Code of Practice (Documents Techniques Unifiés - D.T.U.) n° 52.1 (NF P 61-202).
The bonded floor installation method is appropriate for thin covering tiles (marble, stone or granite of 10mm thickness, ceramic tiles, glass mosaic). It requires few millimeters of mortar adhesive and is particularly convenient in renovation projects in the replacement of existing thin coverings (carpet, wood parquet or ceramic tiles). The reference document that regulates this installation mode in France is the Book of Technical Specifications of Execution (Cahier des Prescriptions Techniques d’exécution - C.P.T) n° 3267 of the CSTB.
Check the adequacy of the supports (allowable supports, planeness, slope, humidity…) according to the reference documents mentioned above.
Refer to the tables of allowable dimensions and thicknesses summarized in the reference documents mentioned above. Lay the tiles from different boxes or crates in order to distribute the natural shades of the material harmoniously.
Verify the necessity to install a sound insulation layer.
For the bedded floor installation, the bedding mortar is composed of sand and bonding agents. Check the conformity of the components and their mix composition as summarized in the Unified Code of Practice (D.T.U.) n° 52.1 indicated above (clean water, washed sand, preferably white cement and/or hydraulic lime that doesn’t stain the covering material…). It is recommended to lay a damp-proof membrane in order to cut the capillarity between the support and the bedding mortar and to resist the passage of dampness.
For a bonded floor installation, verify that the mortar adhesive is adequate to the support, that it doesn’t stain the covering material and that it has been granted a positive Technical Opinion.
Make sure that the expansion joints of the main structure, the subdivision joints of the floor covering and the peripheral joints are executed according to the reference documents mentioned above.
The joints between tiles or slabs are filled with cement grout or ready-made jointing grout. For interior floors, the width of thin joints is usually between 1.5 and 2mm for natural materials like marble, stone and granite. Thin joints should not be less than 1mm thickness since laying tiles or slabs edge-to-edge is forbidden. For full-body ceramic tiles with rectified edges, the joints are at least 2mm wide. For more information, refer to the reference documents mentioned above.
Allow the freshly installed floor covering to dry completely. A long drying period is necessary for hand-made terracotta and natural materials like marble and stone in order to evacuate dampness’ rises (in the form of stains, laitance, salt…).
During that period, ventilate the room without covering the finished floor covering, and clean the surface with a slightly damp floorcloth in order to prevent efflorescence from accumulating on the surface.
If initially requested by the client, rubbing and crystallization can be done on the floor covering in natural material such as marble and stone. This work is to be done in accordance with the code of practice and in consideration of the intermediate drying periods. The floor finishing can be honed (rubbing only) or polished (rubbing and crystallization).
It is recommended after the installation and the complete drying of stone, granite, terracotta or slate covering, to apply a water- repellent or an anti-stain product adequate to the covering material and the desired finishing (mat, satin, polished or wet effect). It is preferable to make a test on a small surface first. It is also advisable to repeat this treatment regularly (every year or two, depending on the covering material and its destination).
For the maintenance of natural materials and terracotta, clean the surface with clear water damped floorcloth. It is possible to use particular soaps or to dilute “Marseilles soap” in a large volume of clear water to avoid soap residuals. Never use aggressive products like scale remover detergents, bleaching water, solvents or abrasive sponges.
The above information is not exhaustive and is given for indication only. In no case does it replace the reference documents indicated above, namely the Unified Code of Practice (Documents Techniques Unifiés - D.T.U.) n° 52.1 (NF P 61-202) and the Book of Technical Specifications of Execution (Cahier des Prescriptions Techniques d’exécution - C.P.T) n° 3267 of the CSTB or other ruling norms and technical instructions.