A solid-surface morphology has a rough character that prevents it from being described by Euclidean geometry; fractal geometry is plausible. From considering that the deposition of particles and their detachment significantly influences roughness, an expression based on stochastic modeling techniques was obtained to predict the fractal dimension of a surface based on the dynamics of the processes that occur in it. The model obtained was used to characterize whether fiber in building materials made of poured earth influences the surface's morphology and the effects of erosion