The thesis aims to investigate how a transformation, possible extension, and change of use of an historical building can strengthen the connection to the site’s history and contribute a richer variation and new qualities to a development area. This is done by making a design proposal for a current transformation project called Magasin 405. Magasin 405 is a port warehouse in Oceanhamnen at the center of Helsingborg, which is part of the vast urban renewal plan H +. With the renewal plan as basis the project and building is set in context of the city and the area. Based on this and the municipality’s visions a new design and function of the building is created. The focus during the design has been on the building’s historical character and ro...