This paper addresses the issue of the urban transformation of Barcelona’s "second suburbs", working-class neighbourhoods, that arose in the twenties, forming, within the city,fragments of a residual identity at risk of disappearing. In this context it can be found the district of Turó de Font de la Guatlla, an urban enclave, inhabited since its inception by Spanish immigrants, now considered obsolete by the city planning policies. Its analysis allows to open a debate on the definition of preservation and to propose new strategies for heritage conservation. Compared with the conservative approach, which is based on the material qualities of an element, this text describes a participated experience, involving local residents, to protect and enhance the elements of authenticity. A conservation that integrates the preservation of architectural and urban elements with the importance of the consideration of intangible aspects. It aims at enhancing the traces of historical memory and the social practices of use and appropriation of urban spaces for social aggregation.