Instructions For The Laying And Maintenance Of Marble And Natural Stone
General:
Immediately after delivery to the site the tiles should be placed inside, or at least covered to protect them from the wind and rain. Slate, quartzite and sandstone tiles must be carefully inspected by the tile-layer and all traces of dirt and dust removed. Laying should not be started until the tiles are completely dry.
The area where the tiles are to be laid must be protected from cold and damp. The concrete base must be allowed to dry for at least 28 days. To avoid the penetration of any dampness from the concrete base, a double layer of polyethylene should be placed between the concrete and the stabilized sand-bed (or other covering); the single waterproof sheet below the concrete base in insufficient. The edges of the double sheet must be raised to, and cut off at, the level of the joint between floor and skirting board. Whenever the length to be tiled is more than 10m or the area more than 50m2, it is necessary to include an expansion joint, located traversals through the sand-bar and mortar. The procedure is the same for wall tiles.
Laying:
General procedures of good workmanship should be followed when laying the tiles (see also STS 45.30). Carefully mix the tiles to achieve a harmonious appearance of colours and shades. With white marble, slate or quartzite, it is recommended to coat the back of the tiles with BELTRAMIX at least 24 hours before laying. The flooring should be laid on a bed of stabilised sand with a maximum thickness of 5 cm, composed as follows: washed white sand mixed with white cement, (500 kg of sand to 50 kg of cement), slightly dampened and consolidated. (NB for white marble, only white sand should be used). The tiles should be laid in a bed of mortar, composed of 1 m3 of white sand, plus 300 kg of white cement with BELTRAMIX added to the mixing water.
Limestone as Blue Stone, Comblanchien,
Calibrated tiles are always laid on a hard ,dry base BELTRAFLEX: a double coating of adhesive is indispensable; on the tile and on the base.
After laying the tiles it is important to keep the surface free of water. Moreover, the joints must be left open for several days (a minimum of 14 days in winteror in damp weather), so that the moisture in the base has a chance to dry out. Lay with joints of about 2 mm to 3 mm. The mortar for grouting is BELTRAJOINT, available in beige, white grey or black.
Slate, quartzite, sandstone, antique limestone and external tiles, are laid with wider joints (approximately 1 cm); the grouting is then composed of 2 parts of fine sand and 1 part of cement, without colouration. It is important to constantly clean the tiles to avoid leaving traces of cement. Do not inhibit evaporation, which takes place through the tile, by covering with PROCELL, impermeable carpeting,etc., during the drying of the floor. Temporary floor protection, so that other work may be continued, should also be avoided. These actions will seriously increase the risk of floor deterioration. If necessary, use white cardboard.
Underfloor Heating
Where tiles are laid on a floor with under floor heating, it is recommended that the supplier,s instructions are strictly adhered to. It is always advisable to work with the correct joints. The use of tiles with irregular dimensions increases the risk of tile breakage and cracking. Tiles must be laid with BELTRAFLEX on a dry and insulated base. A galvanised metal reinforcement must be incorporated in the base. Expansion joints must be used every 8 linear metres or every 35 m2. Before starting the tiling work, the under-floor central heating should be turned on, step by step, increasing 5 degree per day, starting 28 days after the laying of the concrete base. After 3 days at maximum temperature, the heating can be reduced, step by step, to it,s normal temperature and tile laying can begin.
Exterior Tiling:
When laying tiles outside, it is advisable to take the following details into consideration:
The drainage foundation beneath the base should be composed of dry granular concrete on a bed of gravel. Composition of the granular concrete: 150 kg cement per m3 granules 8/22 or 10/20. The tiling should be laid with a slope of 1.5% to avoid water stagnating on the surface of the tiles: the slope must be such that the water will flow away from the house. The connection between the tiles and the wall of the house must be lower than the damp course in the wall. Expansion joints must also be installed every 8 linear metres or per 35m2.
