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J..H. h( EI�FEI f�f X ASSOCIATES File No. S-2314-1 August 15 , 1978 PAGE SEVEN expansive. Although less expansive than the Stockton "adobe" clay, it is our opinion that foundations , floor slabs and i exterior concrete placed on the clay soil, are still subject to potential damage due to heaving or shrinkage of the soil with changes in moisture content. For this reason, we recommend the foundations for the proposed residential homes extend to a depth where moisture fluctuations are minimal. In addition, we recommend that the subgrade soils beneath concrete slab- I on-grade floors be properly moisture-conditioned. Our detailed recommendations for foundations , floor slabs and other items are presented in the following sections of this report. Foundations _ We recommend that the proposed residential homes and the pertinent structures be supported on spread and continuous footings extending a minimum of 18 inches below lowest adjacent soil subgrade, interior or exterior, whichever controls . A continuous footing around the perimeter of each structure and between raised floor and slab-on-grade portions of the home is recommended. Since foundations are likely to be supported on the native undistrubed clay soils , we recommend that the soil bearing pressures be limited to 1 , 000 pounds per square foot for dead load, 1 , 500 pounds per square foot for dead plus permanently applied live load, and 2, 000 pounds per square foot for the total of all loads , including wind or seismic forces . The minimum recommended width of continuous footings is 12 inches . We recommend that all foundation excavations be cleaned of any soft or loose pockets of soil . We also recommend that ! the footing excavations be filled with concrete as soon as Possible after excavation to minimize the shrinkage and drying of the bearing soils .