Abstract: Flooring structure having a rigid horizontal base and a tile or terrazzo top flooring layer. This flooring structure also has a crack isolation layer between the base and the top flooring layer. The crack isolation layer comprises a hard, essentially rigid material which is in load bearing relationship with the base and the top flooring layer and which extends over about 50 percent to about 80 percent of the surface area of the crack isolation layer as measured in the horizontal direction. The crack isolation layer may be in the form of a fracturable sheet or in the form of pilings. The remaining portion of the crack isolation layer may be occupied by a deformable material.