Plans FOUNDATION CERTIFICATION c " 0
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LOT 5 OF "ESTATES AT ASPEN RIDGE", / �il eL-
CITY OF TIGARD, WASHINGTON COUNTY, OREGO\1
LOT
1 LOT LOT 01/29/2020
2 S8816'20"E 82.00' 3 i REGISTERED
PROFESSIONAL
LAND SURVEYOR
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OREGON
JANUARY 11, 2005
PUE—PUBLIC UTILITY EASEMENT ROBERT R. RETTIG
50124LS
a RENEWS: 12/31/20
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S.W. ASPEN RIDGE DRIVE PREPARED FOR
N N WESTWOOD HOMES, LLC
12118 NW BLACKHAWK DRIVE
PORTLAND, OR 97229
I, ROBERT D. RET11G, A REGISTERED LOT
PROFESSIONAL LAND SURVEYOR IN THE STATE OF ESTATES AT ASPEN RIDGE 5
OREGON, HEREBY CERTIFY THAT I HAVE STAKED AKS ENGINEERING & FORESTRY, LLC Ais ORWN: CRC
THE FOUNDATION FOR LOT 5 OF "ESTATES AT 12965 SW HERMAN RD, STE 100 cHKo: RDR
ASPEN RIDGE" WITH HUBS AND TACKS ON TUALATIN, OR 97062 AKS OB:
JANUARY 28, 2020. P:503.563.6151 F:503.563.6152 aks—eng.com 7719
GeoPacific
Engineering,Inc,
Real-World Geotechnical Solutions
Investigation • Design•Construction Support
January 31, 2020
GeoPacific Project No. 13-3036
Westwood Homes, LLC
12700 NW Cornell Road
Portland, Oregon 97229
Phone: 503-715-2383
Via email to: Darringa westwoodhomesllc.com
Subject: GEOTECHNICAL OBSERVATION OF FOUNDATION SUBGRADE
ASPEN RIDGE—LOT 5
12045 SW ASPEN RIDGE DRIVE M51 6,10/Cir_00E3S
WASHINGTON COUNTY, OREGON
GeoPacific visited the site January 27, 2020 to observe the foundation preparation for Lot 5. 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 mostly complete
and extended approximately 1 to 11 feet below the surrounding grade. The foundation bearing
material consisted primarily of basalt bedrock, with native silt soil across the southeast corner.
Probing efforts with a Humboldt hand probe indicated very stiff consistency of the native soils.
The footing layout of Lot 5 is relatively flat, but includes elevated pier pads along the north end.
Tall foundation walls will also be poured along the west and north footing lines. Structural
backfill will be needed between the foundation wall of Lot 5 and Lot 6. Structural backfill will
also be needed between the north foundation wall and the adjacent vertical cut for the elevated
pier pads.
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 1/2 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 1/2-inch of
loose soils are present prior to pouring concrete.
We observed water seeping from the cut at the back of the lot. A wall drain should be installed
behind the wall. Construction should also 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
14835 SW 72ntl Avenue Tel(503) 598-8445
Portland, Oregon 97224 Fax (503)941-9281
Westwood Homes — Lot 5 Aspen Ridge
GeoPacific Project No. 13-3036
construction_ Appropriate 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.
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Benjamin G. Anderson, P.E
Senior Engineer
2 GEOPACIFIC ENGINEERING, INC.