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Project No. JB-569 20 June 2006 Page 9 or equivalent pipe installed on a bed of approximately 3 inches of drain rock. Class 2 Permeable drain rock is and acceptable equivalent for drain rock and geotextile. The subdrain must be placed at the heel (rear) of the keyway/bench with perforations placed downward. The subdrain should be extended to an acceptable outlet using unperforated pipe outside of the drain rock. All subdrain and outlet drain pipe must be placed to fall at least 1 percent. Fill placed within the keyway must be compacted to a minimum of 95 percent relative compaction at a minimum of 3 percent over optimum moisture content. Fill placed above the keyway or above benched areas must be compacted to a minimum of 90 percent relative compaction. The gradient of the exposed outboard surface of the fill must not exceed 2H:1 V. Additional recommendations may be made for fill slope construction depending on the soil conditions encountered. 6.2 Foundations 6.2.1 Conventional Foundation System If the earthwork recommendations included in this report are complied with, the proposed private residences may be supported by conventional foundations established on compacted, engineered fill. Settlement of the proposed structures, supported as recommended, should be less than 1 inch. Recommendations for footing depths and foundation details are included in Table 3. The excavations for footings must be cleaned of all loose materials and debris, and moistened prior to placement of concrete. All footing excavations must be observed by our representative to verify the condition of the bearing material. If any localized areas of loose or soft undesirable subsoil are observed in footing excavations, the excavation for the footings must be over-excavated to firm soil and backfilled with compacted fill under the observations and testing of our representative. All footings should be reinforced with top and bottom reinforcement to provide structural continuity and to permit spanning of local irregularities. The reinforcement of the footing should be designed by a structural engineer. If a different type of foundation system is desired, this office should be called for supplemental recommendations. Such recommendations will be presented as an addendum to this report. ire Korbmacher Engineering, Inc.