The construction on the soft clay which extends in many areas in Egypt is considered a big challenge. The soil of Port-Said is one of the inverted soils such as Frankfurt and Shanghais. Herein, extended poly-styrene (EPS) geofoam was used to replace the soft soil in order to control settlement under raft foundation. In this study, a two-dimensional finite difference numerical method was adopted. This numerical method was first verified against experimental data and then used for the analysis of the raft using EPS in a parametric study. The parametric study was extended to consider the change of the density and thickness of geofoam layers and the number of floors. Comparison was made between cases with geofoam replacement and those without geofoam. Discussion for the numerical results was performed and conclusions were drawn.