This may result in rapid spoiling of soft stone and brickwork leaving the mortar standing proud like a shelf, to collect yet more water, increasing the masonry's deterioration. Chemical action between brick or stonework and cement often takes place causing unsightly salt staining and in the case of some sandstone very rapid spoiling. To some extent modern methods of construction have reduced, but not entirely eliminated, these problems. Mention must also be made of aggregates since the characteristics of Portland cement, including high frost resistance, made it possible to use soft lime sands. These sands increase the density of mortars and renders, aggravating water retention problems.
Walls breath better and moisture can evaporate.
Mortars and renders do not set too hard. Thermal movement can be accommodated without damage. Expansion Joints can be avoided. Insulation is improved and cold bridging reduced. Reduced risk of condensation.