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Report wort ;.3 `2011 4 46Ql1 k4 .,t s , ; � F:'`�'� =, , k , , w 6eoP innineerno. Inc Real -World Geotechnical Solutions Investigation • Design • Construction Support October 3, 2011 Project No. 11 -2315 J T Roth Construction 1 S T Z d 1 r _ 12600 SW 72nd Ave. #200 Portland, OR 97223 1►.t S 'zb ( — C5CD/V7 Phone 503 - 473 -3497 Fax 503 -624 -0239 Subject: ROCKERY WALL FINAL AND FOUNDATION EXCAVATION REVIEW LOTS 9 AND 10 MOUNTAINVIEW ESTATES 12467 AND 12499 SW ST. ANDRENS LANE TIGARD, OREGON Reference: GeoPacific Engineering, Inc., Rockery `Nail Design. Lots 9 and 10 Mountainview Estates. 12467 and 12499 SW St Andrews '_are Tigard, Oregon. September 26, 201 GeoPacific Engineering Inc. designed a gravity ;ucxery retaining wall for construction. 3 -foot maximum height wail tiered wails were at the rear ;north side of the ict This brief letter :s tc verify that GeoPacific has reviewed the constriction of the rockery retaining wall. The wall review was performed by our design engineer. The subgrade consisted of predominantly . medium hard, weathered basalt rock and some stiff Willamette SILT Formation, The cut wall • - backcuts were as expected in the design. The 'boulder sizing and orientation of placement was in accordance with the design. The quality of the boulders and extensive crushed drain rock backfill was considered adequate. Based on our site observations, we conclude that the new rock retaining walls were generally constructed as designed GeoPacific Engineering Inc. also visited the site to review the house foundation excavation on Lot 10 only for subgrade and bearing conditions. We understand that the proposed residence is a two -story single - family home with a tall crawlsp ce. The excavation exposed weathered rock and stiff native clayey silt. The observed subgrad is considered adequate for spread foundation support to a maximum allowable bearing pressute of more than 1,500 psf Footing -to -slope setbacks were not an issue. Within the limitations of scope, schedule and budget, GeoPacific attempted to execute these services in accordance with generally accepted professional principles and practices in the fields of geotechnical engineering and engineering geology at the time the report was prepared. The homeowner should be made aware that a rockery wall is a flexible wall system that could periodically require some maintenance and /or engineering review. 13910 SW Galbreath Drive, Ste 102 Tel (503) 625 - 4455 Sherwood, Oregon 97140 Fax (503) 625-4405 O c t. 3. 20 4 4`P .; R ` No. 2282 P. looplinipt � , Project No. 11 -2315 Mountain View Lots 9 and 10 Sincerely, GeoPacific Engineering, Inc. \ PROF GI NF �� G 47 ' . ,� � -• OREGON D ES D. ®� XPIRES: 06/30/20,1 James D. Imbue. G E Geotechnical Engineer 2