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Engineering,Inc.
Real-World Geotechnical Solutions
•investigation
•Design
•Construction Support
October 11, 2017
Project No. 17-4481
Kurt Dalbey
Mission Homes NW, LLC
PO Box 1689
Lake Oswego, OR 97035
FOUNDATION SUBGRADE REVIEW
LOTS 2 AND 5 MISSION MEADOWS
TIGARD,OREGON
GeoPacific Engineering Inc. visited the site to review the single-family home foundation subgrades
at the above referenced lots. In our opinion, the observed subgrades are 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 and/or settlement) are 1 inch and% inch, respectively, over a span of 20 feet. At the time
of our site visit, the excavations were complete, between 0.5 to 1 foot in depth, which exposed dry,
medium stiff, native clayey-silt. These materials probed 1/2 to 4 inches and are considered
adequate to support the planned foundation loads. Footing-to-slope or footing-to-wall setbacks
appeared adequate. Lots 2 and 5 had large roots that were removed. The footings are being
deepened in these areas.
Due to relatively impervious 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 72nd Avenue Tel(603)598-8445
Portland,Oregon 97224 Fax(503)941-9281
GeoPacific.Enghtr eering, Inc.
Job No. 17-4481
Lots 2 and 5 Mission Meadows
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.
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EXPIRES:06130/20 .
James D. Imbrie, G.E.
Geotechnical Engineer