7818 LARIMER RD B Geotech Report 2022-10-25

SURFACE DRAINAGE A detailed drainage plan should be prepared by us once the site grading plans and project design is completed. In general, proper surface drainage should be maintained at this site during and after completion of construction operations. The ground surface adjacent to buildings should be sloped to promote rapid run-off of surface water. We recommend a minimum slope of six inches in the first five horizontal feet for landscaped or graveled areas. These slopes should be maintained during the service life of buildings. Landscaping should be limited around building areas. Irrigation should be minimal and limited to maintain plants. Roof downspouts should discharge on splash -blocks or other impervious surfaces and directed away from the building. Ponding of water should not be allowed immediately adjacent to the building. It is important to follow these recommendations to minimize settling of the foundation elements throughout the life of the facility. Construction means, and methods should also be utilized which minimizes saturation of soils during construction. Again, positive drainage away from the new structures is essential to the successful performance of foundations and flatwork, and should be provided during the life of the structure. Paved areas within 10 feet of structures should slope at a minimum of 2 percent away from foundations, and landscape areas within 10 feet of structures should slope away at a minimum of 8 percent. Downspouts from all roof drains, if any, should cross all backfilled areas such that they discharge all water away from the backfill zones and structures. Drainage should be created such that water is diverted away from building sites and away from backfill areas of adjacent buildings. EARTHWORK CONSTRUCTION Once the grading plans are finalized, we should be contacted for specific earthwork recommendations, especially the stability of adjacent structures, shoring requirements, cut slopes, and construction dewatering. In any case, site grading should be carefully planned so that positive drainage away from all structures is achieved. As a minimum, following earthwork recommendations should be followed for all aspects of the project. Fill Placement: Fill material should be placed in uniform horizontal layers (lifts) not exceeding 12 inches before compacting to the required density and before successive layers are placed. If the contractor's equipment is not capable of properly moisture conditioning and compacting 8-inch lifts, then the lift thickness shall be reduced until satisfactory results are achieved. Proposed Construction Project No: 0470-WA18 January 24, 2019 Page No: 12 of 17