What is the best way to get the surface lime off the family house

Painting latex (to be diluted with water) can be! The purpose is to increase the adhesion of lime, because it is the roof, temperature changes, repeated contraction and expansion, such as adhesion is not enough, it is easy to cause the displacement of the lime layer and fall off, strong adhesion, it will not be easy to fall off, but cracks are difficult to avoid Oh!