Pathologies in the placing of ceramic coatings

Daily find us with pathologies in ceramic coatings, although the technicians and materials for his placing have developed and improved enormously in the last 15 years. We have of a wide range of materials of placing for each type of baldosa ceramic and support in function of his absorption of water and superficial texture, but still can us find with deteriorations in the ceramic coatings in spite of the correct use of the materials of placing.

Analysing the distinct methods of placing and the evolution of the materials of construction in the last 6000 years, obviously can detect easily some enormous changes, so much in the characteristics of the baldosas ceramic, as in the construction and manufacturing of the supports. But it seems, that want to forget us of a factor, that already does thousands of years the teachers of work took into account, that precisely are the movements of the support. It does centuries was usual the placing of the baldosas ceramic on a layer of sand, that fulfilled the function of amortiguador between the support and the final coating. The colocadores more experienced can confirm us, that till lately applied this layer for desolidarizar the coatings of the support, while in the actuality is more usual the monolithic placing of the coatings to the support.

Know, that all the supports move and in addition to a distinct form to the ceramic coatings. They exist four distinct reasons for the movements of the support:

1. Movements by retracción

2. Movements by humidity

3. Movements by thermal sensors dilatation

4. Movements by curvature

In any one of the cases a small movement of the support can cause the desprendimiento of the coating of his support of placing or the apparition of fissures in the same. For example, the sum between the retracciones by loss of water and the retracciones chemical in the supports in basic cement (soleras of concrete, recrecidos of mortar) can be until 1 mm in 1 m. This movement can seem us insignificant, but if it moves the alone support 1 mm in 2 m, raises the rigid coating placed on this support until 2 cm in his centre. Also the sensitive supports to the humidity and the placings of ceramics in zones with permanent humidity have the same problematic. Especially the sensitive supports to the humidity (derived of the wood, plaster and anhidrita) increase drastically of volume in contact with water, what causes the desprendimiento of the ceramic coatings. But also it has to take into account, that the change of the degree of humidity in supports cementosos, as for example, in glasses of swimming pools and outsides in general, can be the cause of important movements in the support. Besides it is frequent the presence of water in the young supports, that arrives through the capilares to the surface and breaks the union between the adhesive and the coating, by what is indispensable the application of an impermeabilización in any application of ceramics in zones with presence of water.

The greater cause of pathologies by movements in the placing of baldosas ceramic is represented by the movements by thermal sensors dilatation in outsides. Each material used in the construction has a coefficient of distinct dilatation. While the baldosas ceramic usually have a coefficient of dilatation around 0,007, the coefficient for the majority of the supports in basic cement is upper (0,012). For the calculation of the dilatation of a material by each metre, has to multiply the change of temperature in Kelvin by the coefficient of dilatation. If, for example, we imagine us a terrace with baldosas ceramic to full sun in the month of August, know that the ceramic can reach in his surface a temperature of 80°C. During the night or under a storm, this temperature can go down in little time to 10°C, what comports a change of temperature of 70°C. If we multiply these 70°C with the coefficient of dilatation of the ceramics (0,007), results a movement of 0,49 mm/m. Of the same calculation for the support results a movement of 0,84 mm/m. The support moves 0,35 mm/m more than the baldosas ceramic. It seems little, but this means, that in 5 m a support moves 1,75 mm more than the baldosas ceramic placed on. Of this form create tensions very important in the zone of union between the support and the coating, that have to cause fissures in the baldosas placed, if they are properly adhered to the support. If on the contrary the adherencia of the baldosas to the support is insufficient, is programmed the lifting of the same.

Like last type of movement can find us with the curvature of the supports. This phenomenon is usual in the placing of baldosas ceramic on forged, that during his life suffer arrows. Also in this case it creates a transversal strength between the reverso of the baldosas and the surface of placing, that only can remain compensated by means of a plate of desolidarización.

This clear, that in a lot of occasions has to desolidarizar the ceramic coating of the support, to avoid that the movements of the support transmit to the ceramics, or vice versa. Besides it is important a correct impermeabilización of the support in zones with permanent humidity or in the case to work with sensitive supports to the humidity.

Thus Schlüter-Systems has developed the plate of impermeabilización and desolidarización Schlüter-DITRA, that fulfils these functions and that guarantees a correct operation of the ceramic coatings in extreme situations and on critical supports. Because there are not unsuitable supports, but alone methods of inappropriate placing.

Schlüter-DITRA Is a plate of polietileno with a drawing cuadriculado in relief with form of tail of milano. The reverso of the plate is recubierto by a geotextil. Used jointly with coatings ceramic, Schlüter-DITRA acts like plate of impermeabilización, plate of desolidarización on critical supports and compensates the pressesure of steam in the case of appear humidity in the support.

To) Impermeabilización

Schlüter-DITRA is a plate of polietileno waterproof with a density of diffusion of steam of water relatively high. The plate Schlüter-DITRA, placed properly in the union between plates, as well as in the zones of delivery of walls or other vertical structures with floors, acts like plate of impermeabilización. Of this form, Schlüter-DITRA protects the support of the humidity or of the leak of substances that can damage it.

b) Desolidarización

Schlüter-DITRA desolidariza The coating of the support and neutralises the tensions that produce between the support and the revestimiento ceramic derived of the different movements. The plate also absorbs fissures of the support and avoids his transmission to the ceramic coating.

c) Compensation of the pressesure of the steam

Thanks to the channels of open air that find in the inferior part of the plate, Schlüter-DITRA compensates the pressesure of the steam of water in the case of presence of humidity in the support.

d) distribution of load

Schlüter-DITRA transmits to the support the loads to that sees subjected the ceramic coating like result of the traffic through the gaps cuadriculados with form of tail of milano of his top covered by a fine layer of adhesive. This increases the resistance of the baldosas ceramic placed on Schlüter-DITRA.

1. The support has to be levelled, be sufficiently resistant and not containing elements that could hamper the adherencia of the plate. Measures of nivelación of the support have to realise previous placing of the plate Schlüter-DITRA.

2. The election of the adhesive with that has to place Schlüter-DITRA will depend of the type of support. The adhesive has to adhere to the support and anchor mecánicamente to the geotextil of the inferior part of the plate Schlüter-DITRA. On the majority of the supports can apply adhesive hydraulics of fine layer. Nevertheless, it will be convenient to check that the materials chosen can use jointly.

3. The adhesive will apply on the support with a flat toothed of 3 x 3 or 4 x 4 mm.

4. The plate Schlüter-DITRA previously cut to measure will place with the geotextil immediately in the layer of adhesive applied and presionará on the same with a fratás or roller of pressesure following the same steering. Has to respect the open time of the adhesive. During the placing of the plate Schlüter-DITRA, this will have to range properly. Likewise, it is convenient that the placing of the plate was realised by two people so that they can help . The plates will place to testa.

Notices: If the plate Schlüter-DITRA places like layer of desolidarización, the zones of union and of delivery will not have to cover with the band Schlüter-KERDI-Band. If it places like layer of impermeabilización, will have to follow the recommendations indicated in the corresponding section.

5. To avoid that the plate Schlüter-DITRA placed suffer damages or despegue of the support recommends , for example, place tablones wooden (especially, in those places where transport material). These tablones will avoid that the plate was subjected to excessive loads. Other recommendations are, for example, avoid his prolonged exhibition to the solar radiation or to the precipitations when it place in external zones. Likewise, previous application of the adhesive, will have to delete any accumulation of water in the drawings cuadriculados.

6. The baldosas ceramic can place immediately after the application of the plate with an adhesive adapted for the type of baldosa ceramic that want to place . It is recommended to fill up first the cavities of the drawings cuadriculados with the adhesive and to continuation apply more adhesive with the flat toothed. To continuation will place the baldosas without leaving gaps in his reverso. Especially if they place baldosas in pavimentos with a high mechanical aggression and in external zones, will have to avoid these gaps in the reverso and has to follow the recommendations of placing. The size of the teeth of the flat has to adapt to the format of the baldosa ceramic. Has to take into account the open time of the adhesive.

In combination with ceramic coatings can use the plate Schlüter-DITRA like impermeabilización, if impermeabiliza properly the unions between plates and deliveries to other elements of construction. For the realisation of waterproofing solutions in swimming pools, bathrooms and humid zones in interiors recommend the utilisation of our plate of impermeabilización Schlüter-KERDI.

Schlüter-DITRA Protects like this the support in front of leaks of humidity or of aggressive substances. In the unions between plates has to apply the adhesive raincoat Schlüter-KERDI-COLL and places the band Schlüter-KERDI-Band of 12,5 cm of width. For the impermeabilización of the zones of delivery between floors and walls will place in the floor the plate Schlüter-KERDI-Band on the plate Schlüter-DITRA, whereas in the walls, Schlüter-KERDI-Band will adhere directly to the support. The solape of the waterproof bands has to be of aprox. 5 cm. With high presence of water has to apply the waterproof bands with Schlüter-KERDI-FIX.

The placing of Schlüter-KERDI-Band also is recommended in the zones of delivery with fixed structures, such like doors, windows or enclosures of metal, wood or plastic. For the placing of the band has to apply first Schlüter-KERDI-FIX on the structure. The remaining part of the band will place to the plate Schlüter-DITRA with the adhesive raincoat Schlüter-KERDI-COLL.

Recommends check in all cases the compatibility of Schlüter-KERDI-FIX with the distinct materials of construction.

The plate Schlüter-DITRA was developed in the year 1987 and during the year 2009 the company Schlüter-Systems supplied roughly 250.000 m² through his network of distributors of ceramics and warehouses of materials of construction in all Spain.

The first field of application is the impermeabilización in the rehabilitation of terraces and azoteas of houses, although it also is increasing the use of the plate Schlüter-DITRA in the construction of new buildings.

The advantage of the plate Schlüter-DITRA in the rehabilitation of houses is his possible placing on supports of ancient ceramics, as, for example, azoteas with rasillas or baldosines Catalan cracked and/or dilapidated. In this case the plate Schlüter-DITRA no only impermeabiliza surfaces with problems of leak of water, but also avoids that the cracks of the support transmit to the new coating. Besides they avoid demolitions and special settings, that especially in the centres of cities can be costly.

In front of waterproofing solutions conventional by means of asphaltic plates or of PVC stand out besides the following advantages:

- The humidity in the layer of mortar of compressesion or distribution of loads between conventional plates and the coating causes efflorescences and breaks by frosts in the coatings. Schlüter-DITRA Avoids these phenomena, since the impermeabilización finds just underneath of the coatings.

- Ideal for his application with problems of height, since they place the baldosas directly on the plate Schlüter-DITRA of alone 3 mm.

- Ideal for rehabilitations, since it can place directly on ancient coatings.

- No only impermeabiliza with guarantee zones in outsides, but also avoids breaks in the baldosas by the movements of dilatation with changes of temperature.

- Effective also for the impermeabilización of floors and inner walls with humidity.

Thus the plate Schlüter-DITRA is the ideal solution to avoid pathologies in the placing of ceramic coatings in interiors and external.