REVIEWED BLD2020-1007+GEO+3.18.2021_4.09.23_PM+2100497OF ELIA,
CITY OF EDMONDS
PLAN REVIEW COMMENTS
PLANNING DIVISION
' p0 425.771.0220
DATE: March 10, 2021
TO: Irina Zubchik; INTERIORARDOUR@GMAIL.COM
FROM: Michele Q. Szafran, Planner
michele.szafran@edmondswa.gov
RE: Plan Check BLD2020-1007
9220 Cascade Dr.
Single Family Deck Repair and Expansion
On behalf of the Planning Division, I have reviewed the above building permit application. During review
of the subject submittal it was found that the following information, corrections, or clarifications need
to be addressed. Please respond to the following items, so that review may continue: New comments
are below in red.
Critical Area Checklist: Geotech Report Information Still Needed, see comments below. The reports
provided do not address the critical area code, the Geotech needs to provide a response to the code �,�,/ �
sections referenced and underlined below.1e QED �o� Was L'0ER—e0A2
March 5, 2021: My previous letter states the specific code sections that the Geotech must address, b�
its unclear to me if the Geotech received my letter which states this, so I suggest that you provide efF %71eQ�
this letter to your Geotech so that the code is addressed as previously requested. The Geotech �j�j
report must review the criteria for develor)ment in or near aeoloeical hazards identified in ECDC 03 �8/2/
23.80.060 and .070 and must contain the elements listed in ECDC 23.80.050 and 23.40.090.D. Please
provide this letter and your proposed site plan to the Geotech.
Additionally, there are two Geotech reports that have been submitted with the same dates, but one
says revised, and one includes additional attachments, also the language between the reports is not
the same, please clarify which is the correct report. Please have the Geotech compile the full report
for submittal which also address the referenced code sections. I have attached the 2 reports
submitted with reference notes highlighting the differences between the reports. The reports must
contain the elements listed in ECDC 23.80.050 and 23.40.090.D., for example I see no mention of the
height of slope, or slope gradient within the report. Also, I do not see any specific mention of code
sections ECDC 23.80.060 and ECDC 23.80.070.
February 4, 2021: A critical areas determination was completed by staff on February 2, 2021
(CRA2021-0006) which identified the property is within a Geologically Hazardous Area for landslide
hazards. The proximity of the proposed project area lies within 50 feet of a steep slope and thus will
require the geotechnical report to specifically address ECDC 23.80.060 and ECDC 23.80.070. Please
have the Geotech report address the referenced code sections.
October 27, 2020: A critical area checklist is required prior to issuance of a building permit. Please
complete and submit a Critical Area Checklist via my building permit. Per the city GIS web map it
appears that there may be a potential erosion and landslide hazard mapped within 50 feet of the
subject property. Please note that if a landslide hazard (slope 40% or greater) is present within 50 feet
of the subject site then a geotech report will be required and the report would need to specifically
address ECDC 23.80.060 and ECDC 23.80.070. Please submit a critical area checklist for further
review of the subject property. Further clarification regarding if any studies or reports will be
required will be provided to you following the critical area determination. (When submitting via my
building permit select the following; Application type: Land Use; Project Type: New; Activity Type:
Critical Areas).
2. ADDRESSED
3. ADDRESSED
4. Notice on Title: STILL NEEDED. Pursuant to critical regulations (ECDC 23.40.270.6), sites with field -
verified presence of critical areas and/or critical area buffers for which a permit application is
submitted shall as a condition of approval, record a notice of the existence of the critical area and/or
critical area buffer against the property with the Snohomish County Auditor's Office. Following
review of a Geotech report the Notice on Title document along with recording options will be
provided to you.
5. ADDRESSED.
if you have any questions of me, please contact me via email at michele.szafran@edmondswa.gov.
March 18, 2021
Mr. Charles Williamson
9220 Cascade Drive
Edmonds, WA 98020
Re: Geotechnical Recommendations
Proposed Deck
9220 Cascade Drive
Edmonds, Washington 98020
Dear Mr. Williamson,
This report summarizes the results of my site inspection and geologic research of the
property located on SW corner of 12th Ave and Cascade Drive in Edmonds. It is
understood that the existing upper deck structure at the SW side of the residence will
remain, and that a new upper deck will be constructed as an 8 foot extension to the
north as shown on Drawing A107.
Site Conditions
Geologically this property is underlain by glacial deposits (Qva) consisting of dense silty
sands with gravel. These glacial soils were exposed at shallow depths over the rear yard
area, and they have provided excellent support for the existing deck footings. Field
observations of west facing slope below the rear property line was made to confirm there
was no evidence of landslide movement. Existing fill soils were placed on the westerly
side of the rear yard, and there was some minor shallow soil erosion and downslope
movement of these surficial soils.
Field measurements indicate that the top of this slope is located at least 28 to 32 feet
from the west side of the new deck structure. The existing dense glacial soils are
providing excellent support to the house and deck foundations, and there has been no
indication of settlement or lateral movement of these footings, Additional field
observations of the rear yard area showed no signs of settlement of lateral movement in
the rear yard area due to the location of the steep slope below the west property line.
Geotechnical Recommendations
On the basis of my field inspection and geologic research this proposed new end story
deck will be supported on new concrete footing pads. Structural design of these footings
may be based on a soil bearing pressure of 2500 psf with a passive pressure of 250 pcf.
Each footing pad should be inspected to confirm the adequacy of the bearing soils prior
to installing the new deck posts. All new deck foundations will be installed outside of
the critical area buffer, and there will be no adverse impact related to the steep slope.
These recommendations are in compliance with Codes 23.80.o6o and 23.80.070.
On the basis of my plan review and engineering evaluation there will be no adverse
impact of the new deck structure on the stability of downslope area on this property that
is considered stable and resistant to future landslide movement. A field memo can be
provided for submittal to the city of Edmonds following a final site inspection of the new
deck structure.
Please call me if there are any questions.
Respectfully,
M. A
IN
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Robert M. Pride, P. E.
Principal Geotechnical Engineer
dist: (1) Addressee
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