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Project No. JB-569 20 June 2006 Revised 18 October 2006 Page 5 4.3.3 Flooding The site is not located within the 100-year flood zone according to FEMA National Flood Insurance Program maps (FEMA, 19971. 5.0 DISCUSSIONS 5.1 General The recommendations contained in this report are based on the assumption that the soil conditions encountered during construction are similar to those disclosed by our exploration. If variations are noted during construction, Korbmacher Engineering, Inc. should be notified so that we can supplement our recommendations, as applicable. As discussed earlier, till was encountered in the proposed Lot 3 to a depth of about 5 feet. Based on a site topography and reconnaissance, the fill could be as deep as 8 feet, however, it may be deeper. Prior to site development, this fill will need to be excavated and recompacted. This fill will also be buttressed as part of developing Lot 3. The owner should be aware that the depth and extent could be much larger than expected during site grading. Exploration trenches should be performed prior to site grading to help determine the depth and extent of the fill. Recommendations for placing compacted, engineered fill are discussed in the following sections of this report. Provided the earthwork recommendations are followed, it is our opinion that the proposed residences may be supported on a pier and grade beam system established in native soil. As discussed earlier, we anticipate the building pads to be level. We recommend that the subgrade soils for floor, and garage slabs, where used, and exterior flatwork be replaced with 12 inches of non-expansive compacted fill, Class 2 material or an approved equivalent placed on moisture-conditioned, compacted fill. The non-expansive fill should extend at least 2 feet beyond the floor and garage slab areas and exterior flatwork. Proper drainage must be provided to prevent moisture from penetrating beneath foundations, concrete slabs-on-grade, and pavements. If moisture penetrates the soils beneath these areas, there could be some movement and resulting cracking/distress. Recommendations to help reduce the movement of the foundations and concrete slab-on-grade floors/flatwork are discussed in later sections of this report. f Korbmacher Engineering, Inc.