The facade is the showpiece of any building. The commonly used light-wet method is increasingly giving way to other solutions, such as ceramic cladding, stone, wood or ventilated facades. An interesting aesthetic treatment that can distinguish a building is the use of ceramic tiles on the facade.
Construction details
Designing a ceramic tile facade is not particularly different from designing a roof. The arrangement of layers is similar to that of the slope. The structural element, instead of rafters, is a grate attached to the wall with consoles. Structural elements can be wooden or metal (steel or aluminum). Due to the specifics of the solution and economic aspects, steel consoles protected against corrosion and a wooden grate are most often used. The whole is completed with insulation material and a membrane.
Such a solution is designed like any other ventilated facade, taking into account the dead weight of the structure and covering, wind pressure/suction and other less frequent loads (e.g., crowd pressure, installation elements). In addition to calculating the grid structure, spacing of consoles and selection of appropriate anchors, it is required to calculate the number of thermal insulation fasteners. The minimum number of them is indicated in the appendix to PN-EN 1996-1-11and , if the insulation manufacturer does not have other guidelines included in the national or European technical assessment, it is 4 pcs/m².
If the building has additional fire requirements, they also need to be included in the facade design. Tile as a non-combustible product assigned class A1 does not deteriorate the fire classification of the partition.
Tiles on the facade - a trend in architecture
Photo: Wienerberger. Actua 10
Fixing of tiles
Both on steep roofs (with a slope of more than 60°) and facades, mechanical fixing of each tile is required. The elements are laid 'loosely' so that material changes due to thermal expansion do not cause structural failure. The advantage of facades made of tiles with such an arrangement is that no additional expansion joints are required, since the designed tolerance on the locks compensates for thermal expansion of the material. Tiles on the facade are fixed using screws and side clips.
Tiles on the facade - a trend in architecture
Photo: Wienerberger. Frédéric MIETTE PHOTOTANDEM ART Architecture Angélique Thomas
Thermal calculations
According to technicalconditions2 , the heat transfercoefficient of external walls in residential buildings should not be higher thanUC(max) = 0.20 W/(m2K). This coefficient is calculated in accordance with PN-EN ISO 69463 for an inhomogeneous partition. In addition, air voids in the insulation layer (when there is a single layer of thermal insulation joined to the face) and metal fasteners passing through the insulation layer are taken into account. If the correction does not exceed 3% of the U-value, it is not taken into account. With well-ventilated ventilation gaps, which occur with a facade laid with tiles, according to the standard, the thermal resistance of the gap and the layers occurring behind the air void are ignored, and the outward heat transfer resistance is increased from 0.04 to 0.13m2 K/W.
A key point is the aesthetic connection between the roof and facade. Most often, the connection is realized by using a concealed gutter. It is important that there are no thermal bridges at the connection point, so in some cases it is necessary to use inserts of insulating material with better thermal performance. In some models, the connection can be made with mansard roof tiles, and in the case of products where such elements are not present, you can make use of flashing and water drainage in the ground floor.
Tiles on the facade - a trend in architecture
Photo: Wienerberger Patrimone_Architect_Zampone Architectuur
Restrictions on use
The requirements that a building should meet are imposed by building regulations and the provisions of the zoning plan or development conditions. The zoning plan, which most often specifies the maximum height of the building, the permissible range of slope gradients, etc., rarely restricts the developer's ability to create elevations. Due to the basic requirements contained in the regulations, the system can be used throughout Poland, in all wind zones, of course, after preparation of the structural design.
According to §225 of the technical conditions, façade cladding elements should be attached to the building structure in a way that prevents them from falling off in the event of a fire, within a time period no shorter than that resulting from the required fire resistance class for the exterior wall. Wienerberger was the first manufacturer in Poland to receive a positive opinion from the Institute of Building Technology on the possibility of using plain tiles on the facade in low and medium-high buildings, meeting the 30-minute requirement.
Tiles on the facade - a trend in architecture
Photo: Wienerberger Rovearchitecten
Durability the main advantage
In addition to its high aesthetic value, a tile facade is characterized by high durability at a relatively low price compared to other ventilated facades. Ceramic tiles are not affected by weather conditions over time, as evidenced by older buildings and the condition of the covering that can be found on them. The color of ceramic tiles is obtained in the firing process, so it remains stable over a long period of time. Koramic tiles also have a 30-year frost resistance guarantee, confirming the quality and durability of the product.
Tiles on the facade - a trend in architecture
Photo: Wienerberger. Rovearchitecten
Maciej Brzozowski, M.Sc.
[1] Eurocode 6 - Design of masonry structures - Part 1-1: General rules for reinforced and unreinforced masonry structures.
[2] Regulation of the Minister of Infrastructure of April 12, 2002 on technical conditions to be met by buildings and their location, as amended.
[3] EN ISO 6946 Building components and building elements - Thermal resistance and heat transfer coefficient - Calculation method.
