BRICKS, STONE & MORTAR
Over time, due to heavy rains, frost and general bad weather, stone, bricks and mortar will eventually break down.
Not only is this aesthetically displeasing but can also lead to problems such as water ingression and dam, So what's the answer ? Bricks can be replaced as can stonework it can also be re-pointed but with an appropriate material like quicklime mortar. Cement mortar is to hard for Victorian & Edwardian masonry and it also traps water in the masonry bedding.
Although sand and cement certainly has it's place in the construction industry, it's application can be causing problems when used on older buildings.
Old buildings were often built using lime mortar which is a lot more porous than sand and cement. This allows for the breathability of the building which is exactly what they need. So when it rains, your building will soak up some of the moisture due to the nature of stone, bricks and mortar. If the correct products for the building are used, they will then quickly dry out.
Often (but not in every case) where dampness can be found there is sand and cement nearby. This is due to the low level of permeability in sand and cement. Not only can this cause dampness within the building but also the defacing and deterioration of the bricks themselves. Bricks are often more porous than sand and cement thus leading them to soak up most of the moisture.
Lime is a natural product that is vapour permeable and very good at reducing the water content in masonry after rain.
Eroded bricks and stone are often the results of poor quality repairs undertaken with a cement-based mortar trapping water behind the cement itself.
Penny roll tuck pointing in a quicklime mortar