Wear courses of terraces, balconies and loggias are exposed to particularly rough and changing conditions. In winter, the surface temperature may drop to minus 30°C and in the summer, as a result of exposure to intense sunlight, the temperature may reach up to 70°C and then, in night or due to rain falls, drop again to 10 – 12°C. Another stress may result from temperature difference between the topmost and the bottom layer of the terrace, balcony or loggia slab. Therefore, the works should be performed by a skilled and experienced contractor using a dedicated set of materials. In the case in question, one should also remember to provide expansion joints as follows: on the side, at the building wall and one anti-contraction joint in the pressure and cladding courses.
Proper order of operations involve:
- application of the insulating and movable course of two coats of torch-on membrane, covered with 0.2 mm thick PE membrane. This layer serves as a damp-proof course and ensures independent displacement of the reinforced concrete slab in relation to the upper courses.
- application of the pressure course of ALPOL AP 400 cement screed or ALPOL AZ 135 levelling mortar, minimum 30 mm thick with a minimum slope of 1.5%. This layer is intended to create stable base for the topmost course, insulating and movable course and the thermal insulation course. The pressure course is also the part which accepts the load resulting from the use and thermal expansion of the surface of a balcony or loggia.
- application of the undertile insulation layer comprising ALPOL AG 707 silicate-polymer primer for mineral substrates and a double coat of ALPOL AH 752 two-component flexible sealing mortar, using ALPOL T1 sealing tape. The undertile insulation prevents from penetration of moisture to the lower layers and reduces the base moisture build up under the tiles, which could lead to freezing damage.
- fixing tiles, e.g. porcelain tiles, with the use of liquefied adhesives: ALPOL AK 516 highly-flexible or, ALPOL AK 517 medium-coat adhesive for ceramic tiles (full bonding layer!). This layer protects all the layers laid previously from weather conditions and provides operating and decorating properties.

Only such order of layers and careful pointing of the tiles and expansion joints is a guarantee of full water repellent properties and trouble-free use for long years.