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FP~q~_i : ~ERRA FIRMA GEOTECHNICAL PHONE NO. : 541 567 8178 Jul. 58 1999 02: 19PM P02 26910 Fern Ridge Road Sweet Home, Oregon 97386 Phone/Fax (541 ) 967-8178 July 30, 1999 FIL James Grlffiths Excavating, Inc. P.O. Box 1136 Canby, OR 97013 Attn: RE: James Griffiths BERGER RESIDENCE 11664 BUNTING LANE AURORA, OR 97002 This letter addresses concerns raised by Marion County officials regarding the slope adjacent to the subject residence. The residence is a manufactured home installed in 1998 in accordance with county permits and regulations. Subsequent to the installation, but before issuance of a final occupancy permit, s sleep, vegetated slope adjacent to the home was covered with loose soil. No stripping, benching or other site preparation was made before placement. The homeowner estimates the maximum thickness of the soil placement between one and two feet. The county is concerned that the loose fill on the vegetated slope presents a stability hazard. Terra Ftrma Geotechnical (herein referred to as Terra Firms) was requested to visit the site, observe the present conditions, and make recommendations as warranted addressing the long-term stability of the site, particularly with respect to the safety and stability of the residential structure. Carol at James Griffiths Excavating, Inc. verbally authorized the work on July 23, 1999. Field Observations Terra Firms visited the site on July 26, 1999 an observed the site conditions in the presence of Carl Berger, the homeowner. Mr. Berger provided anecdotal information and photographs of the foundation construction of the home. The home Is founded on three concrete strip footings, each one four feet wide. The east footing, that is, the footing adjacent to the slope, is four feet deep. The remaining footings are shallower. The horizontal setback of the footing from the edge. of the slope is about seven feet at the ground surface. At Ihs footing base, the setback Is estimated at 12 feet. The slope adjacent to the east side of the house descends steeply to a concrete retaining wall about four feet high. The slope angle and lenglh were measured with a hand-held clinometer and a fiberglass tape. The overall slope dimensions from the top of the retaining wall to the top edge of the slope are about 37 degrees over a slope distance of 11 feet, corresponding to a slope height of about 7 feet. or a gradient slightly steeper then I- 1/2H:1V.