The Arts Centre of Christchurch is a locally, nationally and internationally significant set of heritage buildings, which gained even more significance as the devastating earthquakes of 2011 destroyed so many other parts of the city’s built heritage. The repair, restoration, strengthening and conservation of these historic buildings was an extremely complex task from a structural point of view, with each separate structure presenting its own set of challenges and demands. To compound the technical difficulties of the site, variability of construction materials and the extent of the damage, the structural strengthening elements need to be ‘invisible’ as far as possible, in order to preserve the unique and precious heritage features.