An historic building survey of Colchester Castle was conducted during renovations to the interior throughout 2013 and 2014. The survey conformed largely to Level 3 (although sometimes Level 2 or 4).<1> A laser scanning survey took place, which captured survey data as a point cloud. The results from this survey were used to produce annotated CAD drawings of the internal elevations of the castle. Wherever possible the main phases of construction and development of the castle were identified, along with architectural details and significant fixtures and fittings. The main outcome of the survey was the production of detailed elevation drawings of the internal elevations and structures of the castle. In addition an extensive catalogue of photographs was compiled along with detailed room descriptions. The room descriptions detail the two main phases of the Norman castle construction (where visible), the Roman foundations, 18th-century reconstructions and other developments made to the castle. These room descriptions are to be used alongside the elevation drawings, which have been annotated, marking the phases of construction and the rises within those phases.