Wood is more and more seen as a sustainable solution to offset carbon emissions from constructions. In response and in parallel to this, the research in robotic timber construction is evolving rapidly, pushed by Industry 4.0 technologies and the integration of digital and physical robotic assets. This paper presents an approach for the design and assembly automation of layered timber structures, with the use of a flexible cell based on collaborative robots. Advanced assembly procedures and digital design of non-standard timber structures are here established and integrated. The automation process is here enhanced by the (1) use of feedback systems based on the location and force signals, (2) the introduction of a flexible robot setup with automatic screwing, and (3) human-collaboration to provide immediate assistance to the robot in the case the signals do not match the defined assembly conditions. The paper discusses the development and use of a Cyber-Physical System to govern the entire construction process, including reflections on the integrated approach to the design, modelling and simulation of the process.