A mild thermal modification system was developed, investigated and taken to demonstration level in Wales over the period 2012 to 2014. The aim of the process were to enhance machinability and working quality of homegrown timber, to add value, and to allow application in markets such as cladding and joinery. This paper provides the context, an overview and some key outputs from the project. In addition, one demonstrator project, provision of cladding for a factory and visitor centre on Anglesey, has allowed ongoing investigation of the timber during weathering, and any issues arising in service. The thermally modified larch performed well as a cladding timber, and after four years exposure shows colour change, but very limited other alterations arising from weathering.