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File: 218267 November 30, 2018 It would be reasonable to use soils from the basement excavation to raise portions of the site grades to improve drainage of the site. The placement of fills at the site is expected to include: utility trench backfill, basement wall backfill, slab subgrade materials, and finished drainage and landscaping grading. These and all other fills should be placed in conformance with the following guidelines: Fills may use organic-free soils available at the site or import materials. Import soils should be free of construction debris or other deleterious materials and be non-expansive. A minimum of 3 days prior to the placement of any fall, our office should be supplied with a 30 pound sample (approximately a full 5 gallon bucket) of any soil or baserock to be used as fall (including native and import materials)for testing and approval. All areas to receive fills should be stripped of organics and loose or soft near-surface soils. Fills should be placed on level benches in lifts no greater than 6 inches thick (loose) and be compacted to at least 90 percent of their Maximum Dry Density(MDD),as determined by ASTM D-1557. If native expansive soils are used for fill at the site, then the soils should be placed at 3 to 5% over Optimum Moisture Content and be compacted to between 85 to 90 percent of their MDD. In pavement (concrete or asphalt)areas to receive vehicular traffic,all baserock materials should be compacted to at least 95 percent of their MDD. Also, the upper 6 inches of soil subgrade beneath any pavements should be compacted to at least 90 percent of its MDD. If fills in excess of 3 feet thick are to be placed, our office should be contacted for further recommendations. Temporary,dry-weather,vertical excavations should remain stable for short periods of time to heights of 5 feet. All excavations should be shored or sloped in accordance with OSHA standards. Permanent cut and/or fill slopes should be no steeper than 2:1 (H:V). However,even at this gradient, minor sloughing of slopes may still occur in the future. Positive drainage improvements(e.g.drainage swales, catch basins, etc.) should be provided to prevent water from flowing over the tops of cut and/or fill slopes. Foundations —At Grade Due to the presence of highly and moderately expansive site soils,the at grade foundations will need to penetrate into the deeper, more stable soils. We recommend a pier and grade beam foundation system be used. Piers should penetrate a minimum of 10 feet below lowest adjacent grade. The piers should have a minimum diameter of 16 inches and be nominally reinforced with a minimum of four #4 bars vertically. 7