REVIEWED PLN BLD2022-0076+GEOTECH LETTER+1.21.2022_2.35.23_PM+2634830Robert M. Pride, LLC Consulting Engineer
November 30, 2021
Mr. Jason Duncombe
c/o Richard Okimoto AIA
9924 225th Place SW
Edmonds, WA 98020
Re: Geotechnical Recommendations
Proposed Residence Addition
18426 79th Place SW
Edmonds, Washington
Dear Mr. Okimoto,
This report summarizes the results of our site assessment and geologic research on the
residential property located on 79th Place SW in Edmonds. The purpose of this report is
to describe existing site and subsoil conditions, and to provide recommendations for
foundation design.
Site Conditions
This property is relatively flat as it extends over to the top of an existing steep slope that
is located 35 to 40 feet from the rear wall of the existing residence to the rear of the
property. According to geologic mapping for this area this site is underlain by dense
glacial deposits (Qvt) that consist of coarse sands and gravels. Two test pits were
excavated in the rear yard and they encountered these dense glacial deposits at depths
Of 3 to 4 inches below existing grade.
Detailed observations were made of the steep slope area to determine overall stability
conditions of this slope. There was no evidence of any landslide activity or shallow slope
instability, and all existing old trees on this steep slope were stable and remained in a
vertical condition. These dense glacial soils have maintained long term stability on this
steep slope, and they have provided excellent support for the existing residential
foundations that showed no evidence of settlement or lateral movement.
Geotechnical Recommendations
Based on the results of our site investigation and assessment of the geologic conditions
on this site, all new footings should be designed for a soil bearing value of 3000 psf and
a passive pressure of 300 pcf. There will be minimal settlement of the new footings that
will be supported on the very dense glacial soils, and the existing setback from the top of
the steep slope in the rear yard will provide excellent protection to this existing
residential structure.
Robert M. Pride, LLC Page 1
13203 Holmes Point Drive NE Kirkland, WA 98034
The final plans for this project have been reviewed and they are acceptable from a
geotechnical point of view. Appropriate field inspections will be made during
construction and a final field memo will be prepared for submittal to the city of
Edmonds building department.
Please call me if there are any questions.
Respectfully,
Robert M. Pride, P. E.
Principal Geotechnical Engineer
dist: (1) Addressee
rmp: Duncombe79thRes3
Robert M. Pride, LLC Page 2
13203 Holmes Point Drive NE Kirkland, WA 98034