Contribution of joint mortars for stability of masonry construction

Jointing mortars connect the stone of masonry. The kinds of mortar and the joint compounds depend on the type of stones, its dimension, the stone working, the structure of masonry and its bond. The dimensions of stones and the mortar of historic masonry could vary a lot according to the kind of building, its age and architectural style, height and exposition as well as the availability of regional raw materials. The proportion of mortar compared to the proportion of stone within masonry is usually very low, but the compounds, chemical compatibility and technical properties of joints play an important role for the stability and durability of masonry. The paper deals with the choice of mortar for joint restoration at historic masonry, with different techniques and details of application.