The cement rendering of houses has been used for centuries to improve the appearance (and sometimes weather resistance) of exterior walls.Over time, render can be affected by the outside elements, causing some of the render to break down and become ineffective. Water permeates through to the brick, which may be old and porous allowing water ingress. Also, on many older houses, the mortar is weak and porous it too allowing water ingress when damp.
When rendering is compromised by cracks and wear, the solution is to remove the old render and replacing it in a few stages. First priming the bare wall by cleaning it and treating with an SBR agent, then applying a rough coat of sand and cement with waterproofing additive. To finish a top coat would be added which can be finished either smooth or rough, for example with pebble dash. To remove the need for painting, the top coat can be coloured to you preference and applied.