Report (2) GEOPPCIFIC
Real World Geotechnical Solutions
Investigation•Design•Construction Support
April 3, 2021
GeoPacific Project No. 21-5769
Westwood Homes, LLC
12700 NW Cornell Road
Portland, Oregon 97229
Phone: 503-715-2383
Via email to: Darrin Krause at darrin@westwoodhomesllc.com
Subject: GEOTECHNICAL OBSERVATION OF FOUNDATION SUBGRADE
BURTS LANDING—LOT 2
11873 SW PENNY LAME
TIGARD,OREGON
GeoPacific visited the site today to observe the foundation preparation at Lot 2 of the
development. It is our understanding that the planned structure will consist of a single-family
residence utilizing conventional spread footings.
At the time of our arrival,the excavation was complete and extended approximately 1 2 to 18
inches below the surrounding grade. The foundation bearing material appeared to consist of
native silt soils, which were evaluated with a hand probe. Probing efforts yielded 3 to 4 inches
of penetration, indicating generally stiff consistency of the foundation bearing soils. The footing
layout of Lot 2 and the surrounding properties is relatively flat. Footing-to-wall and footing-to-
slope setbacks do not appear to be an issue.
Based on observed conditions, foundation subgrade soils as prepared are considered suitable
to support the anticipated allowable bearing pressure of 1,500 psf. Estimated settlement under
the allowable bearing pressure is 1 inch total, and inch differential, measured over a
horizontal distance of 20 feet.
Care should be taken to avoid saturation or disturbance of footing subgrade soils during and
after excavation. 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 approximately '-int of
loose soils are present prior to pouring concrete.
Construction should include typical measures for controlling subsurface water beneath the
homes, including positive crawlspace drainage to an adequate low-point drain exiting the
foundation, visqueen covering the exposed ground in the crawlspace, and crawlspace
ventilation (foundation vents). The homebuyers should be informed and educated that some
slow flowing water in the crawlspaces is considered normal and not necessarily detrimental to
the home given these other design elements are incorporated into its construction. Appropriate
14835 SW 72nd Avenue Tel (503) 598-8445
Portland, Oregon 97224 Fax(503) 941-9281
Burts Landing,Westwood Homes—Lot 2
GeoPacific Project No. 21-5766
design professionals should be consulted regarding crawlspace ventilation, building material
selection and mold prevention issues, which are outside GeoPacific's area of expertise.
We have prepared this report for Westwood Homes, LLC, and it should not be relied upon by
third parties without consulting GeoPacific. 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 conclusions and interpretations presented in
this report should not be construed as a warranty of the subsurface conditions.
No warranty, expressed or implied, is made. The scope of our work did not include flood hazard
evaluations, environmental assessments, the presence or absence of wetlands; or potential
hazardous substances in the soil, surface water, or groundwater at this site
We appreciate this opportunity to be of service.
Sincerely,
GEOPACIFIC ENGINEERING, INC.
14 �..- ,
OREGO
EXPIRES:06/30/2 2.1
James D. Imbrie, P.E.
Principal Geotechnical Engineer
2 GEOPACIFIC ENGINEERING, INC.