CANOD.pdfRobert M. Pride, LLCConsulting Engineer
December 29, 2015
Mr. Craig Roosendaal
704 Bell Street
Edmonds, WA 98020
Re: Geotechnical Recommendations
Proposed Garage
704 Bell Street
Edmonds, Washington
BLD 2015-1352
Dear Mr. Roosendaal,
JAN I S 2016
auMrxim EONS
Scanr�ied
This report provides supplemental recommendations for the proposed new garage
structure to be built on the northeast corner of the existing residence on Bell Street. The
property is currently occupied by an existing residence and paved parking area, and is
protected with rockery walls around the three sides of the property.
The purpose of this report is to provide recommendations for the new foundations that
will provide support for the east and south sides of the garage structure. The existing
house foundation on the west side of the new garage will be used for support of the roof.
Site Conditions
This site has a gradual slope from the rear of the property toward Bell Street. Existing
slopes created by the original site excavation are supported by low rockery walls that are
standing without stability problems. Observations of the existing residence foundations
showed no signs of settlement or lateral movement. Subsoils consist of medium dense
to dense glacial outwash (Qva) deposits that are suitable for support of the new garage.
::'�;u �,bservations of the existing steep slope areas showed no signs of instability or
surficial soil movement. This property is underlain by dense glacial deposits that will
provide excellent support for the new foundations, and will maintain existing stability of
the steep slope areas.
Geotechnical Recommendations.
The native soils will provide excellent support for the proposed garage foundations and
concrete floor slab. These bearing soils for the new foundations will be encountered at
depths on the order of 1 to 2 feet below existing grades, and a recommended soil bearing
value of 1500 psf may be used for foundation design. Lateral resistance may be
provided by a passive earth pressure of 200 pcf and a sliding friction value of 0.40. The
existing house foundation wall on the west side of the new garage will provide
satisfactory vertical support to the roof area.
Robert M. Pride, LLC Page 1
13203 Holmes Point Drive NE Kirkland, WA 98034
Based on my geotechnical evaluation of the subsoil and steep slope conditions on this
property, it is recommended that all new foundations remain at least 15 feet away from
the top of the slopes. This 15 foot buffer zone will be more than adequate for protection
of the existing house and the new foundations for the proposed additions. These
recommendations are in accordance with ECDC 23.40 — go in the Edmonds code.
It is recommended that all construction equipment be restricted from the 15 foot buffer
zone, and that adequate temporary erosion control measures are installed to prevent
offsite storm water flow and sediment discharge onto adjacent properties. Sufficient
field inspections will be required to confirm subsoil bearing conditions, and to
document onsite erosion control during the new construction.
Roof water collected from the roof area may be discharged into the City storm drain
system or to the street at the lower north side of this property
Summary
We recommend that we provide field inspection and consultation services to verify that
subsurface conditions are as expected. Should conditions be revealed during
construction that differs from the anticipated subsurface profile, we will evaluate those
conditions and provide alternative recommendations where appropriate.
Respectfully,
Robert M. Pride, PE, GE
Principal Geotechnical Engineer
dist: (1) Addressee
rmp: RoosendaalRes2
Robert M. Pride, LLC Page 2
13203 Holmes Point Drive NE Kirkland, WA 98034
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