<br />19 <br /> <br />certerra.com 4660 Main Street, Suite 100, Springfield, Oregon 97478 T: 541.393.6340 <br />3.0 EVALUATION AND FOUNDATION RECOMMENDATIONS <br /> <br />3.1 Geotechnical Discussion <br /> <br />The primary geotechnical factors influencing the proposed construction are the following: <br /> <br />• Presence of potentially highly expansive Fat Clay (CH). As mentioned above, based on our laboratory <br />testing results (Expansion Index Test) on a sample obtained at the subject site on March 20, 2026, the clay <br />at this site has a high expansive potential (i.e. high shrink/swell potential). We do not recommend supporting <br />proposed structures directly on the clay. See detailed mitigation recommendations below. <br /> <br />• Steep slope along the east side of Floral Hill Drive. As mentioned above, there was an 8- to 10-foot- <br />tall, 25-to-30-degree slope, along the east side of Floral Hill Drive/west edge of site (i.e. greater than 2H:1V <br />or about 25 degrees). Due to the close proximity to Floral Hill Drive, the risk that underground utilities <br />may be present near the road, and the risk of potentially undermining the road, we did not perform test <br />pits within the steep slope during our site investigation. However, based on visual observation of current <br />site grades, it appeared that previously placed fill material may be present within the slope. On the date <br />of our site investigation, the slope face was covered with grass and brush, and we did not observe any <br />visual signs of recent ground movement in this steeply sloped area such as tension cracks in the ground <br />surface, erosion channels or large bar e patches of ground. See detailed recommendations below to <br />address any structural improvements or structural fill that may be placed within sloped areas of the site. <br /> <br />Provided the recommendations in this report are adhered to, we do not foresee any major geotechnical related <br />issues that would preclude the proposed development. The factors above are mentioned to draw the attention of <br />the reader to a geotechnical related issue that should be considered during design and construction of the proposed <br />development. <br /> <br /> <br />3.2 General Site Preparation <br /> <br />Test pit locations that fall under or adjacent to structurally improved areas should be excavated to their bottoms and <br />backfilled with properly compacted structural fill (as outlined in Section 3.3 below) at the start of earthwork <br />construction, under the observation of a Certerra representative. <br /> <br />Vegetation, roots, and any other deleterious soils should be stripped from beneath structurally improved areas. A <br />representative of the Geotechnical Engineer should determine the depth of removal at the time of construction. <br /> <br />Utilities will need to be located and rerouted as necessary and any abandoned pipes or utility conduits should be <br />removed to inhibit the potential for subsurface soil erosion. Utility trench excavations should be backfilled with <br />properly compacted structural fill which is constructed as outlined in Section 3.3 of this report.