Lime wash
Even a simple lime wash will help to protect brick or stone, draw out moisture and improve the run off of rain water.
Lime putty is mixed with water to the consistency of thin cream. It is applied lightly in several passes with a broad brush, and dries to a soft, chalky finish, which can be lightly coloured with lime fast pigments.
Stronger colours can be achieved with a thinner wash, more heavily charged with pigment and applied to fresh plaster as it carbonates.
