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Report Oct. 19. 2012 3:06PM No. 3324 P. 1 D © Z5 � INC Zotz-- ,/ �. GeoP die Engineering, Inc. Real-World Geotechnlcal Solutions • Investigation • Design • Construction Support October 19, 2012 Project No. 03 -8449 Stonebridge Homes Job No. '1456 Attention: Andy Thomas Stonebridge Homes 4230 SW Galewood St., Ste. 100 Lake Oswego, OR 97035 Fax 503 -387 -7615 FOUNDATION SUBGRADE REVIEW LOT 85 — ARLINGTON HEIGHTS NO. 3 15284 SW OAKMONT PLACE CITY OF TIGARD, OREGON GeoPacific Engineering Inc. visited the site several times this last week to review the single family home foundation subgrade on Lot 85. In our opinion, the observed subgrade is generally adequate for support to an allowable bearing pressure of 1,500 psf. The expected maximum anticipated total and differential footing movements (generally from soil expansion andfor settlement) are 1 inch and a/s inch, respectively, over a span of 20 feet. At the time of our site visit, the excavation was nearly complete and exposed compact rocky clayey silt fill at the front half of the home and native soil and rock at the rear of the home. These soils are considered adequate to support the planned foundation loads. Footing to wall setbacks appeared adequate at approximately 2H:1V from the base of the wall. Due to relatively impervious clayey silt soils encountered throughout the site, all foundations should incorporate appropriate drainage measures in accordance with the International Residential Code. Adequate crawlspace drainage is not something that geotechnical consultants can verify; the purpose of our visit is for observations of foundation bearing conditions only. Care should be taken to avoid saturation or disturbance of footing subgrade soils during and after excavation. We observed some placement of crushed aggregate to protect the subgrade from wet weather. If footing bearing soils become saturated or disturbed, any softened soil or slough should be removed and replaced with crushed aggregate or additional concrete. In general, footing excavations should be cleaned such that no more than about 1 /2 inch of loose soils is present prior to pouring concrete. 14835 SW 72" Avenue Tel (503) 598 -8445 Portland, Oregon 97224 Fax (503) 941 -9281 • Oct. 19. 2012 3 : 0 6 FM GeoPacific e Inc. Job No. 03 -8449 Lot 85 Arlington Heights No. 3 Our work scope pertains to a geotechnical engineer's foundation excavation review only and the conditions existing and exposed at the time of our site visit. 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. No warranty, express or implied, is made. If you have any questions, please call. Sincerely, GeoPacific Engineering, Inc. PROte y `' GIN% /0 147 OREGON S D. W (MOIRES: 06/30120/2 James D. Imbrie, G.E. Geotechnical Engineer