Masonry is one of the oldest construction materials, which was used for all kind of building applications especially for sufficient compressive strength in combination with good acoustic and thermal properties with low construction costs and solving some durability problems. The production of lightweight masonry block is generally performed by using a highly mechanised industry based on great automation and accuracy which is different from the other concrete types. This production has to match strict standards that describe properties specified for the products. Volcanic slag lightweight blocks (VSLB) are made of volcanic slag, cement and water, which are used in construction of non-load bearing infill walls and slabs. One of the most effective ways to reduce the dead load in a multi storey building is to lighten the weight of the structure. Therefore, natural lightweight aggregates, especially produced from the volcanic slag can be considered as a lightweight concrete aggregate in construction of buildings.