2505 57TH ST SW Geotech Report 2022-10-25

August 29, 2019 Mr. Jeff Davis G-4971 Page 7 concentrated flows can lead to increased soil erosion and rutting. Final site grades should direct surface water away from the building. Subsurface Drainage We recommend that footing drains should be installed alongside perimeter foundation and basement walls. The drains should consist of a four inch minimum diameter, perforated, rigid PVC drain pipe laid at the bottom of the footing or wall with the perforations facing downward. The drain line should be bedded on, surrounded by, and covered with a washed rock or gravel. The drain rock and pipe also should be wrapped with a layer of durable non -woven geotextile fabric. The footing drain lines should be sloped at sufficient gradient to generate flow and should be tight -lined to an appropriate stormwater discharge location or collection sump system. The subsurface drainage lines should not be connected to roof downspout or other surface drainage lines. A schematic illustration of these recommendations is shown in Plate 3 — Typical Footing Drain. LIMITATIONS This geotechnical report has been prepared for the specific application to this site for the exclusive use of Mr. Jeff Davis and his authorized representatives or agents. Any other use of this report is solely at the user's own risk. We recommend that this report be included in its entirety in the project contract documents for reference during construction. Our findings and recommendations stated herein are based on field observations, our experience with similar projects, and our professional judgment. The recommendations presented in this Ietter are our professional opinion derived in a manner consistent with the level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area and within the project schedule and budget constraints. No warranty is expressed or implied. In the event that soil conditions are found to differ from those discussed in this report, GEO Group Northwest should be notified and the relevant recommendations in this report should be re-evaluated. GEO Group Northwest, Inc.