In this paper, a numerical analysis of the shrinkage of slabs found on soil was carried out. Two numerical models of the foundation slab were adopted for the analyses: the first model is the foundation slab, which rests directly on the soil, i.e. Winkler elastic base; the second numerical model is two slabs, i.e. the foundation slab and the substructure (concrete base), which are in surface contact. The Coulomb-Mohr model was used in the analyses. On the basis of the numerical analyses performed, conclusions were made about the influence of the soil substrate on the degree of shrinkage reinforcement.