This is a final year project considering constructional techniques for joining cavity walls. The project is related to an ongoing scientific programme about the restoration of The City wall of Visby located on Gotland. The programme was set by Riksantikvarieämbetet as a reaction to a collapse of the outer masonry wall shell which took place in February 2012.The City wall of Visby is a medieval fortification built out of limestone during the 13th century. The wall is constructed as a cavity wall with two separate masonry shells connected to each other through an intermediate core. During the 14th century the wall was heightened which lead to a higher stress, especially in the outer wall face.