In conservation, earth renders can be used as sacrificial coatings. However, earth presents vulnerability when in contact with water. The application of ecological surface treatments on earth renders can be of great relevance, ensuring their durability while increasing eco-efficiency and extending its range of applications. The behaviour of a ready-mixed earth render applied in situ, on adobe and concrete block masonry experimental walls exposed outdoors with protection, and under controlled laboratory conditions, on hollow bricks, was evaluated after four years. Several superficial treatments were applied on the renders: linseed oil, mucilage of aloe vera and pasta and rice cooking water. The renders were characterized by non-destructive tests. The surface treatment with linseed oil presents good results and improves the durability of the earth render, giving it adequate protection against natural degradation.