Exploring the 'palimpsest' as a device for interrogating the designed environment as a multi-layered entity, this paper will consider its pedagogic value for design, design history and design cultures. Engaging the student as detective, we propose forensic methods as a ‘way in’ to design and designing that includes survey and surveillance, the employment of intuition and narrative reconstruction. Approaching the designed environment as palimpsest reveals the capacity of time to fold back on itself, retrieving elements of the past rather than effacing it and also re-engaging the obsolescent – where ‘an obsolete building is in place but out of time’ (Cairns and Jacobs).

A forensic, interrogative mode draws on methods designers and design historians are often already engaged in but, by speculating on the spaces of design as a pseudo-crime scene we can reveal hidden relationships between people, things and environments – through the collection of clues and the interpretation of traces as signs of more complex processes. At the crime-scene everything is of potential significance, bringing into focus a flat ontology of things and the ‘vibrancy of matter’ (from Jane Bennett). And yet, for detectives as for design students, the time-line of the procedure is key – gathering information, establishing priorities and registering effects – as the investigation moves from the 'scene' to the ‘forum’.

Employing the designed environment as classroom – for designers, a space to design in and for design historians, an active site for learning about design – we aim to challenge the traditional schism between disciplinary territories.