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Geotechnical Engineering Evaluation NGA File No. 961916 Mason Residence Addition and Deck August 24,2016 Everett,Washington Page 21 25 proposed additions and improvements. We have also been provided with a record of survey titled "Caroline Mason," dated February 2015, prepared by Western Engineers & Surveyors, showing the existing site conditions. The existing site features along with the planned addition and deck location are shown on the Schematic Site Plan in Figure 2. SCOPE The purpose of this study is to explore and characterize the site surface and subsurface conditions, and provide general recommendations for the planned improvements. Specifically, our scope of services includes the following: 1. Review available soil and geologic maps of the area. 2. Explore the subsurface soil and groundwater conditions within the vicinity of the proposed addition with a limited-access drill rig. Drill rig was subcontracted by NGA. 3. Map the conditions on the slope below the proposed addition, perform hand-tool excavations,and evaluate current slope stability conditions. 4. Provide recommendations for foundation support for the additions, including minimum foundation embedment. 5. Provide an evaluation of the proposed addition setback from the steep slope. 6. Provide recommendations for earthwork. 7. Provide recommendations for temporary and permanent slopes. 8. Provide recommendations for slab subgrade preparation. 9. Provide recommendations for drainage improvements. 10. Provide recommendations for long-term slope protection and maintenance. 11. Document the results of our findings, conclusions, and recommendations in a written geotechnical report. SITE CONDITIONS Surface Conditions The property is a rectangular-shaped parcel covering approximately 0.80 acres. The site is occupied by the existing single-family residence with a daylight basement in the central portion of the property. An existing upper level deck and lower level concrete patio are located along the northeast portion of the residence. The ground surface generally slopes gently to moderately down to the north and northwest from the southern and western property lines to the top of a steep northeast-facing ravine slope. The steep northeast-facing ravine slope descends from the yard area to the north of the residence and the patio are to the northeast of the residence to the railroad tracks below at gradients in the range of approximately 35 to NELSON GEOTECHNICAL ASSOCIATES, INC.