The project partners aim at producing a unified system of criteria and indicators for the assessment of key competences for professional workers in the construction sector: formal, informal and non formal skills of specific profiles (bricklayers and plasterers) need to be recognized to promote a higher level of transparency of diplomas, certificates and qualifications, to produce common principles for their validation. The choice of these specialists was determined by the fact that they are the most traditional and popular specialities in construction and in all countries. The meaning of the project is, of course, not only a technical / sectoral one: the target groups are people who are working in the construction sector by accident, who are engaged in temporary, seasonal, low qualified jobs, often people with low education and without vocational qualifications or under qualified, sometimes young people and even adolescents situated out of the school system, always people uninterested in traditional methods of education in the informal system and from ethnic minorities and / or from regions with a high percentage of unemployment. Their position does not give the opportunity for long term integration in the labour market, for the recognition of their key competences, for their professional growth through upgrading and qualification. Of the utmost importance is therefore one of the specific aims of the project, that is the development of materials for independent study and self assessment of the acquired skills and competences, directly linked with the certification methodology and the validation system: the pilot phase in the partner countries is planned to be exploited and disseminated in all European countries.