20100310140358445.pdfNovember 1, 2006
Mr. Jon I(vernmo
Hillcrest Construction
P. O. Bax 3121
Everett, IATA 98213-1121
Re: Report on all Inspection
Single Family Residence
47009 77t" Place West — Lot 2
Edmonds, Washington
RMP Project No. 05-125-01
Dear Mr. Kvernmo,
RECEIVED
NOV 0 3 2006
D1:,:,"VEL0PhAEN � SEWCES C rK
UTY OF EDMONDS
Consulting
� . .. . . . . . . . EU
J 11,
At your request and as requested by the City of Edmonds, this letter summarizes the
results of my field inspection of the block and rockery retaining walls recently
constructed on Lot #2 at 17009 77th Place West. It is understood that a separate permit
will be required to cover this wall construction due to its location within the Edmonds
Critical Area.
A site inspection was performed to document existing wall construction, and to confirm
the adequacy of foundation conditions for support of these retaining walls. A two-tiered
interlocking masonry block wall was constructed along north side of the existing
residence. Maximum height of each wall is 4.2 inches, except where the wall drops at the
east and west ends of the property. Both walls are parallel to each other, and they are
about five feet apart at the top of the lower wall. Drain gravel was placed at the base of
these walls prior to backfilling with onsite soils.
On the southerly corner of the residence is a two-tiered rockery wall that extends aroutid
the corner of the property. The lower rockery wall is 2 to 3 feet in height, and the tipper
tier is 2 to 4 feet high. There is a iH:iV setback from the lower wall to the base of the
upper wall. This wall was backfilled with drain rock and onsite soil to the adjoining
property lines. A plan is being submitted showing the wall locations with top and toe
elevations, and the attached Fig -Lire No. 1 shows the construction configuration of both
two-tiered wall systems.
On the basis of iny previous site inspections during excavation for the building pad and
fo-undation installations, these walls were placed on competent native soils. Each layer
of interlocking block is offset one inch with a total of about 5 to 6 inches of back slope
into the final compacted backfill. The rockery walls have a proper back slope if at least
5V:1H, and the base rocks were adequately embedded.
13203 Holmes Point DrivO,,qlP Kirkland_WA 98034
Phone: 425-814-3970 Fax: 425-814-5672
November 1, 2oo6
Mr. Jon I(vernmo
Page 2
Based on my recent site inspection both the interlocking block walls and the rockery
walls are approved as constructed. A stability analysis performed for both block and
rockery wall systems showed that they have a factor of safety in excess Of 1.39 against
overturning.
Please call me if there are any questions.
spectfully,
Robert A Pride, P. E.
Principal Geotechnical Engineer
dist: (2) addressee
rmp: Hillcresffa]1#2
13203 Holmes Point Drive NE Kirkland, WA 98034
Phone: 425-814-3970 Fax: 425-814-5672