This symposium focuses on a practice-based material and architectural attitude towards old and new. What can the terms ‘Weiterbauen’ and ‘affective’ or ‘atmospheric’ conservation mean? How do technical and architectural sustainability requirements relate to spatial ideals? How can old and new typologies reinforce each other from a perspective of layering? How does the need to preserve architectural elements and materials relate to the need to preserve or enhance immaterial aspects such as spatial character, atmosphere, light and other visually, acoustically, and otherwise sensorial qualities? And how do these needs relate to conventions and present day architectural and material choices related to sustainability? What role do changes and adaptations over time and associated layers of time play? And how do projects deal with changing design attitudes and traces of different generations of ‘conservation works’ that are and were always based on time-bound design conceptions? We pose these questions to ‘architects’ but also to researchers, interior architects, conservation architects and various collaborations. Alongside the dialogue between the architect and the building, the dialogue between collaborating partners will take a central position in the symposium. We explore the topic of conservation and transformation as a collaborative design task for architects and heritage architects, their mutual division of roles and the content of these sometimes complementary, sometimes overlapping disciplines. This involves different personalities, signatures, role divisions, design views and areas of expertise. In complex projects, collegial collaborations and consensus are inevitable. On the other hand, all actors operate from different backgrounds and conventions. As the field of transformation continues to grow in importance and complexity, and as the question of the right way to deal with protected heritage also includes questions about non-protected heritage and sustainability, traditional relationships between disciplines are also coming under pressure.