Unstable clay land represent great cracking problem for light buildings over them because of volumetric instability caused by variations in moisture. A generalized solution has been to extract them and substituted by inert soil, thus they become construction trash. There are several foundation solutions to solve the problem of soil, one of which is inverted ribbed slab which generates hollow spaces between the soil and the slab in order to provide sufficient space for the soil movement to prevent damage to the construction. Based of the above concept, this work presents a sustainable and simple alternative for reducing growth of problem soils based on the inclusion of local natural gap material within its structure to reduce instability of clay land, with only previous determination of the void volume. After results, we conclude that gap material placed within the soil decreased their growth favorably and it depended on its natural void volume. In fact total vertical deformation of the soil (by volume) was decreased with only 65% of its value within the voids when the void volume theoretically should be equal to the vertical volume deformed. This is probably due growth pressure soil was redirected into the voids which probably generates greater density in the soil introduced.
