INTRODUCTION
CEN / TR 13548 -
General rules for design and installation of ceramic tiling also specifies the quality requirements of a tiling.
are set out two fundamental aspects:
1. The quality, the "success" of ceramic tiling depend on compliance with the following general requirements:
A. Regularity: the tiling must be flat, without bumps or depressions, with joints straight and regular, without differences in height between adjacent tiles, etc..
B. Durability: the tiling must be able to perform for a long time its technical and aesthetic functions without deteriorating as a result of working stresses;
C. Security: the tiling must be safe, compared to events that may cause injury to people (for example, falls to sliding).
2. Compliance with these requirements should be pursued with the contemporary and indispensable contribution of all the "functions" involved in the realization of the tiling. These functions are: •
production (requirements) of the materials (tiles, adhesives and grout, substrate);
• design of the tiling;
• Run Setup (installation).
A. MATERIAL REQUIREMENTS
A.1. Requirements of the cement basement Test Method
A.1.1. CT: premixed
[1] for concrete slabs. EN13813
A.1.2. C: Compressive strength at 28 days (N/mm2). EN13813
A.1.3. F: Flexural strength at 28 days (N/mm2). EN13813
A.1.4. A1 fl: Fire resistance. EN13813
A.2. Other requirements A.2.1. Planar: the verification of flatness is performed with a straight edge at least 2 m. in length. Place it on the slab in all directions, with this screed that tolerance is 2 mm, one needs to bear in mind that it varies depending on the length of the straight edge used for the assessment of flatness.
A.2.2. Smoothly: the suitability of the surface finish and, therefore, the level of surface roughness depends on the type of floor you have to install. For example, a rough surface to promote drying of the porous substrate and improves the adhesion of plasters and adhesives. If however, you want to get a perfectly smooth mirror, for example where you should place a resilient floor, it is best applied on the surface of the screed leveling products specifically designed for this purpose.
A.2.3. Cleaned the surface of the substrate must be perfectly clean. Dust, dirt and debris must be removed as they can interfere with bonding to the pavement slab.
A.2.4. Without cracks: the presence of cracks on drying shrinkage is caused by one or more of the following factors: excess water in the dough, the aggregate is too fine grained, contains excessive amounts of cement. Before installing the floor is necessary to seal any cracks monolithically.
A.2.5. Compact: the screed must be presented in compact and homogeneous surface and throughout the thickness. The presence of layers or areas with less consistency, more brittle, is a symptom of poor mechanical properties that cause detachment of the floor.
A.2.6. Seasoned and dimensionally stable: the period of aging / maturation is one of the most important requirements for a cement. In fact, the laying of ceramic tiles and stone slabs should be performed on mature, who have already explicit most of the hydrometric withdrawal, thus avoiding the formation of cracks after the laying of the floor able to get the break and detachment of coating. The curing time for a screed "traditional sand and cement is about 7-10 days per cm in thickness (thickness of slab up to 7 cm, temp. Amb.15-30 degrees, about 50% rh.). The waiting time, so if you are using mortars traditional cement, can be particularly long (1 month). This time is greatly reduced by using special binders or premixed rapid setting and drying.
A.2.7. Dry: the residual moisture should be consistent with the expected values \u200b\u200bfor the laying of the floors are sensitive to moisture and uniform throughout the thickness of the substrate. For cement-based screeds are considered acceptable moisture levels below 2% in case you need to lay a wooden floor, of 2.5-3% in the event that we should lay PVC, rubber or linoleum. The anhydrite screeds must have a value of residual moisture below 0.5% regardless of the type of coating (in the case of underfloor plaster: 0.2%).
A.2.8. Mechanical resistance: the mechanical strength, and thickness must be adequate for its intended use and the type of floor to lay. In general, the compressive strength of a screed for domestic, suitable for any coating must not be less than 30 N/mm2.
A.3. Requirements to install ceramic
product group sec. classification UNI EN 14411 - Bla (porcelain stoneware).
test method requirements: ISO 31006
A.3.1. Length and width: ISO 10545-02, ± 0.5%
A.3.2. Thickness ISO 10545-02, ± 10%
A.3.3. Orthogonality ISO 10545-02; ± 0.5%
A.3.4. Flatness ISO 10545-02, ± 0.3%
A.3.5. Water Absorption ISO 10545-03; <= 0,5%
A.3.6. Flexural ISO 10545-04; ≥ 15N/mm2
A.3.7.
Coeff. expansion. term. lin.: ISO 10545-08; 9μm / m K-1
A.3.8. Resist. Chemical: ISO 10545-13; No alterations.
A.4. Requirements of the adhesives (adhesive type C: cement according to EN 12004)
Classification and technical specification of the adhesives are covered by Standard EN 12004 Adhesives for tiles - Definitions and specifications. " The main types of adhesives are: • Adhesives
cementitious (C): mixture of hydraulic binders, aggregates and organic additives to be mixed with water or liquid additives immediately before use. • Adhesives
dispersion (D): mixtures - paste ready to use - organic binders in the form of aqueous dispersion of polymer, organic additives and mineral fillers. • Adhesives
reactive resin (R), a mixture of synthetic resins, mineral fillers and organic additives, in which hardening occurs by chemical reaction. Available as an adhesive to one or two components
For each type can be identified several classes related to the performance framework, according to the following: •
1. Adhesive normal
• 2. Improved adhesive •
F. Fast-curing adhesive
• T. Adhesive Slip reduced
• E. Adhesive with extended open time
test method requirements A.4.1. Open time: EN 1346, EN 12004
A.4.2. Slide. on vertical wall: EN 1308, EN 12004
A.4.3. Initial adhesion to Traz.: EN 1348, EN 12004
A.4.4. Accession Traz. after heat: EN 1348, EN 12004
A.4.5. Membership Traz. after immersion. in water: EN 1348, EN 12004
A.4.6. Adhesion strength after freeze / thaw cycles: EN 1348, EN 12004
A.4.7. Transverse strains: EN 12002, EN 12002
A.4.8. Compressive strength: EN 196
Adhesives Type C are the most widely used, even in public spaces. With the stickers available to the designer of bedding materials that could allow - at least in principle - be applied to almost any type of tile in all media at any target environment.
adhesives are mixtures of several constituents packaged, marketed in various forms (powder, paste, powder + liquid + liquid paste), with which they are prepared in construction of pasta, or hydraulic setting and hardening chemical used just as entrapment of ceramic tiles. In general, the thickness of this bedding is of the order of a few millimeters, although there are special adhesives for greater thickness, the order of 1.5-2 cm. Both the mortars as stickers, to varying degrees depending on the composition, are characterized by variations in size - usually shrinkage - during ripening. Necessary condition for these withdrawals do not lead to internal stress levels are dangerous for the integrity of the tiling is that the thickness of the setting is as uniform as possible. In order for this condition is satisfied, it is necessary that:
• the installation surface is smooth, ie no significant departures from flatness. Any deficiencies found shall be removed by applying an appropriate layer of leveling or adjustment, and varying the thickness of the setting as needed. The CEN Technical Report cited above, taking up a concept expressed in different national rules on the laying of the tiles, states that "... in the case of installation with adhesive, the deviations from flatness of the finished coating
depend on departures from flatness of the media ...", to emphasize precisely the non-eligibility to apply adhesive to compensate for varying thicknesses of surface irregularities;
• the gradient of the project - for example, in a floor where it is necessary to ensure the flow of water - should be made in the structure itself, or acquiring a Special screed slope. E 'rather unfair and risky, even in the case of laying with cement mortar, groped to make the gradient by varying the thickness of the setting.
The development of adhesives has always accompanied the technological development of the tiles, and the gradual broadening the use of tiles. Certainly met the favor of the ceramic tiles would be smaller without the availability of adhesives compatible with the new types of tiles, with new media types / structures to be tiled, with new areas where the tiles have recently been applied, with stringent technical requirements of these new applications. Even in the case of adhesives, the problem is to choose and specify from time to time, in a very wide range, the right product. And even in this case - as in the choice of tiles - the designer must be based both on the technical specification of the adhesive, prepared according to the first mentioned, on both directions - usually complete and detailed information - provided by the manufacturers.
A.5. Requirements for sealing tile Classification and Material Specifications for joints are covered by Standard EN 13888 "Sealants for tiles - Definitions and specifications." The main types of materials for joints are: •
cementitious grout (CG), a mixture of hydraulic binders, aggregates organic and inorganic additives, to be mixed with water or liquid additives immediately before use. • Sealants
reactive resin (RG), a mixture of synthetic resins, mineral fillers and organic additives, in which hardening occurs by chemical reaction.
For cementitious grouts can be identified several classes related to the performance framework, according to the following: W =
sealants reduced water absorption
A = sealants high abrasion resistance.
B. DESIGN OF TILING In the case of floor tiling, focused on the choice of an adhesive suited to the product and operating conditions, there are several options to be taken into account the characteristics of the surface and, again, the operating conditions:
Direct installation with adhesive, applies only support dimensionally stable (ie with flexibility, low compressibility and deformability) and smooth surface (without substantial deviations from flatness and share project)
[2] . Some specific observations are necessary, with regard to floor tiling, the tiling on the mechanical strength in relation to the risks of chipping tiles, cracks, etc.. The operating conditions of a pavement can be very strict in terms of massive mechanical stress. In order for the tiles can withstand these high stresses, must be met in the following two conditions:
B.1. Needs to be met by the ceramic tiling
B.1.1. security needs of the patrons of the environment or public space: the tiling must be safe, compared to events that may cause injury to people (for example, falls for sliding)
B.1.2. aesthetic and furnishing: the tiling must be flat, without bumps or depressions, with joints straight and regular, without differences in height between adjacent tiles, etc..
B.1.3. requirements of durability: the tiling must be able to play for a long time its technical and aesthetic functions without deteriorating as a result of working stresses;
B.2. Requirements of ceramic tiling
1. The tiling must rely on the cooperation of the media, which must be sized in relation to mechanical stress of exercise, and if necessary reinforced with a special slab reinforcement and load distribution, in addition to meeting the requirements mentioned. (Requirements of the slab)
2. The tiles must be reliably anchored to the substructure. Each posting should be prevented, because the portions of loose tiling lose their collaboration support and face a high risk, very close to certainty, to break down. It must therefore be treated with great care, the choice of the setting and the adoption of implementing measures aimed at achieving a compact bedding. A higher guarantee of uniform compactness of the setting you can have by requiring the adoption of the technique of "buttering". So, while the adhesive is normally applied only on the surface to be tiled, in the tiling should be provided that the adhesive is applied on the surface of installation, both on the back of the tile. (Requirements of the adhesive).
To meet that need ques'esigenze ing tile is properly laid in a proper system installation.
There are two installation systems, classified according to the extent of leaks:
less than 1 mm • Width: No joint;
• Size greater than 2 mm, depending on size and type of tiles: joint installation open.
The use of either system has important repercussions on the appearance of the tiling: the joint setting allows a more uniform and continuous surface, while the joints that take place in open joint installation part and highlight the tiled surface a kind of plot, which, given the different color possibilities that there with cushioning materials, may also play an aesthetic meaning. It should also be noted that the open joint method is more long and tedious the joint setting: therefore also more expensive, and this is undoubtedly a significant factor. Normally, the open joint installation is a choice in the case of tiles manufactured by extrusion (terracotta, clinker), because this method of forming a generally does not provide sufficiently accurate control of dimensions to allow the perfect combination of tiles. In the case of the products formed by pressing, both systems can be employed. But there are different circumstances, be carefully evaluated case by case basis in the design phase especially the floors, which may lead them to choose as a solution more secure and reliable, the open joint installation.
Those circumstances are:
• the open joint method can significantly reduce the modulus of elasticity, and therefore the rigidity of the coating layer: while in the joint setting the coating practice is about as a continuous slab, hard as it is a single tile in the open joint method of coating layer shows clearly its structural articulation, with distinct elements and, within certain limits, with some possibility of relative movement. In these conditions, the induced voltages from any differential movements between the various layers making up the system on the coating normally reach levels much lower than those expected in the case of joint setting, so you can, with this system of laying on a relatively effective in controlling the risk of detachment and lifting of the floors;
• the open joint installation makes it less influential any dimensional differences between the tiles. In the joint setting it may be difficult to match perfectly in two adjacent tiles, in accordance with the dimensional requirements of the standard. In other words, the joint setting may reveal precisely at the joints, small discontinuities and irregularities, however, these sometimes valuable to worsen the appearance of the tiled surface. The clearer separation between the tiles that involves the laying open joint contributes to the effect that having less effect on the aesthetic quality of the surface;
• the open joint method allows better control of the smooth and durable fill the joints. In fact, the joint setting flight consists mainly of a very thin space is inevitably one of tile: the crack size by force is not constant, is filled with great difficulty, and often unevenly, even though the product filling is relatively fluid. The predictable consequence is the risk of separation of parts of the filling, dirt, water and substances of the process, even potentially aggressive, thus opening access to the interior of the system. The open joint installation is in this respect, less problematic and risky.
For these reasons, all tiling, and especially those where there is a need for hygiene, should always be specified open joint installation.
[1] Premixed cement-based powder to be mixed with water ready to use on site.
[2] This model is also due to "pose Direct adhesive on existing pavement ", a technique commonly practiced in the restoration of flooring also in public spaces. Obviously, the dimensional stability, strength and integrity of the pavement above, as well as the availability of space needed to accommodate the overlapping tiles, are essential in order to apply this model, and thus save the demolition of the existing coverage.
FOR INFORMATION ABOUT THE TOPICS COVERED CONTACT Arch. MARIANO VICTOR BAVARO:
