Interpretation of mortar analysis The aim with the present report is to describe the usage of testing as a tool for assessment and documentation of historical renders, plaster, joint and masonry mortars. The report contains a short description of the technical properties of the mortars, the analytical methods and sampling method and field documentation. The main part of the report concerns what question can be answered using testing and how the results can be interpreted. There is furthermore a short part about analysis of repair mortars and suitable test for a quality control program for small scale local production of lime binders.