Expansive soil resistant foundation system

An expansive soil resistant foundation system adapted to alleviate potential pressures exerted on the foundation system due to expansion and contraction of expansive soil, comprising:

• a foundation frame having a foundation, the foundation including a plurality of footings, a plurality of support walls extending upward from the foundation and footings to form a grid pattern defining spaces therein, and a ceiling slab atop the support walls, the ceiling slab being adapted to support a building superstructure thereon;
• a main swell duct defined in each space in the grid pattern;
• at least one sub-swell duct disposed inside each of the main swell ducts;
• at least one vent extending from each main swell duct and each sub-swell duct, the at least one vent expelling trapped air;
• and
• a drainage system distributed throughout the foundation frame to drain groundwater from the foundation system, wherein the drainage system is coextensive with the foundation frame and comprises:
• a plurality of drain pipes communicating with each of the main swell ducts and the sub-swell ducts;
• a main drain pipe coupled to the plurality of drain pipes, underground water inside the plurality of drain pipes flowing into the main pipe;
• and
• a drain collection tank coupled to the main drain pipe, the drain collection tank holding underground water flowing through the main drain pipe.