8920 EVERGREEN WAY THE RESERVE 2025-07-25

Zipper Geo Associates, LLC Reserve at Everett Project No. 1117.01 May 1,2013 indicated on the logs. The possibility of groundwater level fluctuations and perched water should be considered when developing the design and construction plans for the project. Summary of Laboratory Testing Laboratory testing was completed on select soil samples obtained from the explorations. Moisture content testing of weathered Glacial Till samples indicated moisture contents at the time of exploration ranging from about 10 to 32 percent. Moisture content testing of Glacial Till samples indicated moisture contents at the time of exploration ranging from about 7 to 11 percent. Moisture contents of samples tested are shown on the exploration logs in Appendix A. Grain size analyses of two Glacial Till samples were completed. The tests indicate a fines content ranging from about 21 to 27 percent. One modified proctor test(ASTM D1557)was completed on a bulk Glacial Till sample obtained from test pit TP-4. The proctor test indicated a maximum dry density of about 137.4 pounds per cubic foot at an optimum moisture content of about 6.4 percent. CONCLUSIONS AND RECOMMENDATIONS General Based on our subsurface exploration program and associated research,we conclude that the proposed development is feasible from a geotechnical standpoint, contingent on proper design and construction practices and implementation of the recommendations presented in this report. Geotechnical recommendations for design and construction of the project are presented in the following sections. A brief summary of identified geotechnical concerns of particular interest for this project are as follows: • Groundwater and Temporary Excavations: Moderate to heavy groundwater seepage was encountered in some of the test pit explorations. Temporary dewatering measures may be required in order to complete temporary excavations for the building and other structures that extend below the groundwater table. Additionally, flatter temporary cut slopes may be required in areas where groundwater seepage is encountered. • Permanent Drainage Measures: In order to prevent hydrostatic pressures from developing on foundation walls, we recommend buried foundation walls are backfilled with a zone of free draining backfill having a minimum thickness of two feet perpendicular to the foundation walls. A drain pipe should be placed at the bottom of the wall footings to collect groundwater seepage. Depending on conditions observed during construction, a sub-slab drainage system may also be warranted. • Foundation Support on Dissimilar Soils: Approximately three quarters of the building foundations will bear on very dense glacial till soils. The remaining one quarter will be • Page 4