A vital area of importance for any trade skill is the use of approved materials to Building Regulation standard. Not only does the working with quality grade materials impact on the quality level of appearance, long term durability, and health and safety but there are legal requirements, as set out by various regulatory bodies.Candidates undertaking an accredited City & Guilds tiling course will become aware of best working practice, as taught by approved and industry experienced teaching staff. As with all trade skills courses, students studying on tiling courses must be trained to verifiable, mandatory standards of knowledge and skills, with completed NVQ course qualifications as proof of a standard of attainment required to be able to enter the professional construction industry, whether commercial or residential.A properly trained and qualified tiler should be aware of key regulatory standards concerning the selection of tiles for any application, no matter the size or scale of the job. Any material product to be used in the building sector should carry a CE Mark, which is a visible declaration by the manufacturer (or his representative, importer, etc.) that the material or equipment marked complies with all the requirements of all the applicable European Union (EU) directives.The CE mark does not, in itself, represent a 'quality' mark or indicate conformity to a standard but it does indicate conformity to the legal requirements of the EU Directives. The letters, "CE", indicate that the manufacturer has undertaken all assessment procedures required for the product.As of January 2000, any ceramic tile sold in the European Union should be clearly marked on the tile box exterior with a CE mark, along with the manufacturer name and year of production, and a reference number of the Standard and description of the product. Some CE marks may also contain details of technical tests undertaken.Ceramic tiles are classified by their production method, which can either be dust pressed or extruded, and the level of water absorption measured as a percentage. They can be also be glazed or unglazed and conform to the physical, dimensional and chemical resistance properties detailed in British Standard BS EN 14411.Ceramic tile adhesives must comply with set regulations and the BS EN 12004 is the standard which sets out the minimum performance requirements for ceramic tile adhesives in Europe. The document states the designation and classification system for the performance levels of different types of adhesives e.g. cementatious, dispersion, reaction resign.Where a manufacturer classifies his product to a category within the Standard, e.g. CIT, this automatically confirms compliance. However, a product which is CE marked may not necessarily ensure that its performance complies to all of the mandatory requirements in BS EN 12004, but instead, implies that the adhesive satisfies the specific mandated part of the Standard.Applying particularly to cementatious adhesives, it should be carefully noted that a label may make reference to BS EN 12004 and also carry a CE Mark, but it is important to examine the remainder of the text. If the adhesive fails to meet the requirements for heat ageing and freeze/thaw the label should state either NPD (No Performance Determined) or provide a value in N/mm2, which will inevitably be less than 0.5N/mm2.For the professional industry tiler, it is crucial that adherence to standards are maintained in order to further reputation and career. Attention must be given to checking for good quality products which carry a classification rating (e.g. C1TE), a CE Mark and a reference to BS EN 12004, with authenticated data on the label, clearly omitted by low performance adhesives.