CRA19970090aq- 1197000
City of Edmonds
Critical ,Areas Determination
Applicant: Nelson Determination #: CA-97-90
Project Name: Permit Number:
Site Location: 18318 Olympic View Drive Property Tax Acct #: 5656-002-009-0003
Project Description
non -project specific
A site inspection has revealed a site developed with a single family residence, and which slopes
down steeply to the west from Olympic View Drive to the Burlington Northern Railroad right -of
way which runs along the water of Puget Sound. The steep slopes, particular at the western end
of the property appear to be are greater than 40% with a vertical elevation change of more than
20 feet.
Based on the above findings, it is determined that there is potentially a steep slope critical area on
or adjacent to the site. A Critical Areas Study is required to delineate the boundaries of this
potential critical areas, the buffers and setbacks. For the steep slopes, a licensed surveyor must
create a topographic map of the site which indicates all areas which slope 40% or more and have
a vertical gain of 20 feet or more within the 40% slopes. The map must also show the location of
the steep slope buffers and setbacks. .
If the property owner wishes to apply for a specific development permit which they feel would
not impact the Critical Areas located on the site, they may submit their proposal to the Planning
Department for review. If the Planning Department finds that the proposed development permit
will not adversely impact a Critical Area or its buffers, a conditional waiver may be issued on a
project by project basis.
John Bissell
Name
i;;�a�ure
June 19, 1997
Date
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GEOTECHNICAL ENGINEERING STUDY
PROPOSED SINGLE FAMILY RESIDENCE
18318 OLYMPIC VIEW DRIVE
EDMONDS, WASHINGTON
G-0907
Prepared for
Ms. Elizabeth Nelson
c/o Mr. Galen D. Holmquist
Paradise Construction, Inc.
23632 Highway 99, F-11
Edmonds, WA 98026
May 28, 1998
Geo Group Northwest, Inc.
13240 NE 20th Street, Suite 12
Bellevue, WA 98005
Phone: (425) 649-8757
RECE►VSD
SEP 2 9 2000
PERMIT COUNTER
i�'p(� Inc.DEC Group Northwest, est� neotechnical Engineers, Geologists
• &Environmental Scientists
may 28, 1998
G-0907
Ms. Elizabeth Nelson
c/o Mr. Galen D. Holmquist
Paradise Construction, Inc.
23632 Highway 99, F-11
Edmonds, WA 98026
SUBJECT: Geotechnical Engineering Study
Proposed Single Family Residence
18318 Olympic View Drive
Edmonds, Washington
Dear Mr. Holmquist:
We are pleased to submit the report entitled "Geotechnical Engineering Study, Proposed Single
Family Residence, 18318 Olympic View Drive, Edmonds, Washington." This report presents the
results of our site exploration, engineering analyses and our conclusions and recommendations for
steep slope setbacks, earthwork, drainage, foundations and retaining wall design parameters.
We understand that the existing one story house with a daylight basement at 18318 Olympic View
Drive, Edmonds, WA will be demolished and replaced with a two story house. At the time of this
study. We were provided with an approximate footprint for the new house, as shown on Plate 2 -
Site Plan.
The subject site was explored with three borings on April 7, 1998 in accordance with our proposal
dated March' 9, 1998. The subsurface soils encountered in B-1 and B-3 near the east side of the
existing house consists of 2.5 to 4.5 feet of medium dense SAND with gravel, below which is a very
dense gravelly SAND with pebbles and silt. The soils encountered in boring B-2 on the west side of
the existing house consists of 7 feet of loose to medium dense soil which is underlain by dense to very
dense gravelly SAND with pebbles and some silt. Groundwater was not encountered during drilling.
Based on the results of our study, it is our opinion that the proposed single family residence
foundations can be supported on conventional spread footing bearing on the very dense native soil.
Due to the existence of loose soils up to 7 feet encountered in B-2, the western half of the proposed
13240 NE 20th Street, Suite 12 • Bellevue, Washington 98005
Phone 425/649-8757 0 FAX 425/649-8758
May 28, 1998 G-0907
Proposed Single Family Residence Page ii
house be supported on a foundation system consisting of augered reinforced concrete piles bearing
on the very dense native soil. As an alternative, the entire house could be supported on augered
concrete piles. The proposed construction will present a minimal risk of instability to the site during
and after the construction, provided the recommendations contained in this report are implemented.
If you have any questions, please call.
Sincerely,
GEO GROUP NORTHWEST, INC.
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William Chang, PE.
Principal
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Geo Group Northwest, Inc.
TABLE OF CONTENTS
JOB NO. G-0907
page
1.0 INTRODUCTION
1.1 Project Description .............................................. 1
1.2 Scope of Services .............................. .
2.0 SITE CONDITIONS . 2
2.1 Surface Condition ........... • .......... 2
2.2 Subsurface Conditions .................... .
2.3 Groundwater ........................
.................
3.0 SEISMICITY ........ 3
3.1 Seismic History
.............
3.2 Soil Liquefaction Potential ... • • • • • •
.............
4.0 BUILDING SETBACK AND BUFFER ... . . . .
5.0 SLOPE STABILITY EVALUATION .. . . . . . .
6.0 CONCLUSIONS AND RECOMMENDATIONS
.. 6
6.1
General ......................... ...............
Preparation and General Earthwork .............
6.2
Site
7
6.3
Spread Footing Foundations ..................... • •
.....
6.4
Augered Concrete Piles ............. • • • • • • • ................
10
6.5
Slab -on -Grade Floors ....................
10
6.6
Permanent Basement & Conventional Retaining Walls .............
.
12
6.7
Excavations and Slopes ........ • • • • • • • • • • • • ' '
6.8
Drainage ......................
.. 13
6.8.1 Surface Drainage ...........................
13
6.8.2 Footing and Wall Drains .... • • • • • ...............
14
6.9
Driveway Area ................................................. ......................
7.0 LIMITATIONS ........................................................
.. 15
8.0 ADDITIONAL SERVICES ........... • . ...............................
Geo Group Northwest, Inc.
ILLUSTRATIONS
Plate 1 - Vicinity Map
Plate 2 - Site Plan
Plate 3 - Steep Slope Cross Section
Plate 4 - Soil Legend
Plate 5 - through 7 Boring Log
Plate 8 - Typical Basement Wall Backfill & Drainage Details
Plate 9 - Typical Footing Subdrain
Geo Group Northwest, Inc.
GEOTECHNICAL ENGINEERING STUDY
PROPOSED SINGLE FAMILY RESIDENCE
18318 OLYMPIC VIEW DRIVE
EDMONDS, WASHINGTON
G-0907
1.0 INTRODUCTION
1.1 Project Description and Understanding
The proposed single family residence is located at 18318 Olympic View Drive, Edmonds,
Washington, as shown on Plate 1 - Vicinity Map.
Based on our site visits and discussions with you and Ms. Elizabeth Nelson, it is our
understanding that the existing one story single family residence with a daylight basement at the
subject site will be demolished and replaced by a two story residence at the subject site.
We also understand that the City of Edmonds requires a geotechnical study prior to issuing a
building permit due to the steep slope and building setback issues. Therefore, the purpose of the
geotechnical engineering study is to define the subsurface soil conditions in order to address slope
stability, setbacks from steep slopes, foundation support, lateral earth pressures, drainage and
earthwork considerations.
At the time of this study, the detail of the new house plan was not available.
1.2 Scope of Services
Our scope of the work is outlined in our proposal dated March 9, 1998, and they are:
1. Perform a subsurface investigation by drilling 2 soil borings, one at the east and one at the
west side of the proposed house. The borings will be drilled to a depth of 15 to 30 feet,
and soil samples taken every 2.5 feet to detect any zones of weakness in the subsurface
soils. The borings will be drilled using a portable drill rig;
Geo Group Northwest, Inc.
May 28, 1998
Proposed Single Family Residence G-0907
Page 2
2. Collect soil samples to perform laboratory tests and prepare boring logs;
3. Perform engineering analysis to evaluate slope stability, foundations and retaining wall
design requirements;
4. Prepare a geotechnical report with the results of the analysis and prepare conclusions and
recommendations for steep slope setbacks, earthwork, drainage, foundations and retaining
wall design parameters.
2.0 SITE CONDITIONS
2.1 Surface Condition
The subject property is rectangular in shape and approximately 14,000 square feet in size. It is
bordered to the east by Olympic View Drive, to the west by the Puget Sound and by two railway
lines at the bottom of a steep slope, to the north and south by single family houses.
According to the topographic site plan and our site observation, a steep slope with an average
inclination of 46 degrees (103 percent slope) and a topographic relief of 100 feet is situated on the
west half of the subject property. The backyard and the proposed building area are relatively flat
with an average inclination of 7 degrees (12.5 percent slope). Chain link fences were observed at
the top of the steep slope and along both sides of the property line on the north and south.
The existing one story single family house with a daylight basement is located on the east half of
the property with a detached one car garage at the southeast corner of the property at the street
level.
2.2 Subsurface Conditions
According to the geologic map for the area, the site is underlain by Transitional Beds (Qtb) which
in turn underlain by Olympia Gravel (Qog). Transitional Beds were deposited during the Fraser
Glaciation to Pre -Fraser Glaciation, the glacial and non -glacial deposits consist mostly of massive,
thick or thin beds and laminae of medium to dark gray clay, silt, and fine to very fine sand.
Geo Group Northwest, Inc.
May 28, 1998 G-0907,
Proposed Single Family Residence Page 3
Olympia Gravel was deposited during the Pre -Fraser Glaciation and consist of stratified, fluvial
sand and gravel. Gravel is mostly pebble size and is locally oxidized. and weakly cemented so that
it stands vertically in fresh exposure.
The subsurface investigation was conducted by drilling three exploratory soil borings (B-1, B-2,
and B-3) on April 7, 1998. The borings were drilled using portable, low -profile hollow -stem
auger equipment to a maximum depth of 13.5 feet below ground surface (bgs). The locations of
three soil borings are shown on Plate 2 - Site Plan. We estimated the location of our exploration
by using a measuring tape from the existing house. A geotechnical engineer logged the borings
and collected soil samples for further examination and testing at our office.
The subsurface soils encountered in B-1 and B-3 consist of medium dense brown SAND with
gravel and a trace of silt from 2.5 to 4.5 feet below the ground surface. The medium dense
SAND was underlain by very dense gravelly SAND with pebbles and silt. Both borings were only
drilled to 6.5 feet below the ground surface due to the difficulty to drill through the gravel.
Boring B-2 was drilled on the west side of the house in the lawn area. The soils encountered in
boring B-2 consists of 7 feet of loose to medium dense soil underlain by dense to very dense
gravelly SAND with pebbles and some silt.
The soils encountered in the borings at the site match those for the Olympia Gravel (Qog) on the
geologic map.
2.3 Groundwater
Groundwater was not encountered during drilling. However, the ground water table can fluctuate
seasonally, depending on rainfall, surface runoff and other factors.
3.0 SEISMICITY
3.1 Seismic History
The project site is located on a bluff facing the Puget Sound and about 10 miles north of Seattle.
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May 28, 1998 G-0907
Proposed Single Family Residence Page 4
The greater Seattle area has experienced a number of small to moderate earthquakes and
occasionally strong shocks during the brief 155-year historical record in the Pacific Northwest.
The major earthquakes in the region are believed to be associated with deep-seated plate tectonic
activity. Major faults within the region have not been active in the Holocene Age (geologic
period dating since the last glacial retreat 14,000 years ago), consequently, they are not known to
be associated with historical seismicity.
Historical records for the region indicate that the Olympia earthquake of April 13, 1949, with a
Richter magnitude of 7.1, produced ground -shaking of intensity VIII near its epicenter; and the
Seattle -Tacoma earthquake of April 29, 1965, with a Richter magnitude of 6.5, produced a
ground -shaking of intensity IV to VIII on the Modified Mercalli Scale near its epicenter. This
level of ground -shaking is estimated to be the maximum that has occurred in the region during the
155 years of historic record.
3.2 Soil Liquefaction Potential
Although there may be subsurface variations from point to point, we expect the native soil
underlying the subject site consists of dense gravelly SAND. Groundwater was not encountered
during subsurface investigation. Due to the dense nature of the native soil, it is our opinion that
the subsurface soils at the site are not susceptible to liquefaction.
4.0 BUILDING SETBACK & BUFFERS
The City of Edmonds, Edmonds Community Development Code (ECDC), Section 20.15B, dated
August, 1996, sets restrictions on the development of sites with steep slopes (40 percent or
more). The ECDC 20.15B requires a total building setback of 65 feet from the top of a steep
slope which includes 50 feet of buffer setback and 15 feet of building setback. The total building
setback may be reduced to 25 feet (10 foot nondisturbance vegetative buffer plus 15 foot building
setback) if there is a special geotechnical study. Smaller setbacks, or construction on steep slopes
requires an exception from a public hearing pursuant to ECDC 20.1000.010 from City of
Edmonds.
Based on the review of the site plan provided to us, the current plans place the proposed two-
Geo Group Northwest, Inc.
Ma 28 1998
G-0907
y 3 Page 5
Proposed Single Family Residence
story house at least 25 feet east of top of the steep slope which is in agreement with our
recommended 25 foot total building setback (10 foot buffer plus 15 foot building setback), as
shown in Plate 2 - Site Plan.
For the purposes of this report, provided that the recommendations herein are adhered to, it is our
opinion that the proposed single family house can be located closer than the required 65 feet from
the top of the steep slope.
Building near the top of any steeply sloped hillside always has some inherent risk. However, the
risk can be minimized by incorporating a reasonable building setback from the top of the slope,
preventing concentrated surface water runoff from eroding the slope, minimizing disturbance to
the slope, and maintaining the native vegetation both on the slope and above the slope. To
mitigate landslide and erosion hazards, we recommend incorporating all these items into the
design of the subject project.
5.0 SLOPE STABILITY EVALUATION
The subject lot is considered to be a geologic hazard area due to the existence of a greater than
40 percent steep slope with a topographic relief of 100 feet as shown in Plate 3 - Steep Slope
Cross Section.
Based on the subsurface investigation, the undisturbed native soil on the top of the steep slope is
dense gravelly SAND with some pebbles and silt and in our opinion they are not susceptible to
deep seated sliding. However, the surficial loose soil or fill may be susceptible to erosion on steep
slopes, especially where vegetation is removed.
It is our professional opinion that the subject lot is currently stable and will be stable after the
subject construction. The proposed single family house will present a minimal risk of instability to
the adjacent property during or after the construction, provided the recommendations contained
herein are implemented.
Geo Group Northwest, Inc.
May 28, 1998 G-0907
Proposed Single Family Residence Page 6
6.0 CONCLUSIONS AND RECOMMENDATIONS
6.1 General
Based on the results of our study, it is out professional opinion that the site is geotechnically
suitable for the development of the proposed single family house, and that the proposed house can
be supported on conventional spread footing bearing on the very dense native soil. Due to the 7
feet of loose soils encountered in B-2, the western half of the proposed house should be
supported on a foundation system consisting of augered reinforced concrete piles bearing on the
dense native soils. As an alternative, the entire house could be supported on.augered concrete
piles.
Specific recommendations regarding the site development are presented in the following sections.
6.2 Site Preparation and General Earthwork
The proposed structure area should be stripped and cleared of surface vegetation and debris from
the demolition of the existing house. Disturbance to the site should be kept to a minimum to
prevent erosion. Silt fences should be installed around areas disturbed by construction activity to
prevent sediment -laden surface runoff from being discharged off -site.
All structural fill material used to achieve design site elevations below slabs, sidewalks, driveways,
etc. should meet the requirements for structural fill. During wet weather, material to be used as
structural fill should have the following specifications:
Be free draining, granular material, which contains no more than five (5) percent fines (silt
and clay -size particles passing the No. 200 mesh sieve);
2. Be free of organic and other deleterious substances;
3. Have a maximum size of three (3) inches.
All fill material should be placed at or near the optimum moisture content. The optimum moisture
content is the water content in soil that enables the soil to be compacted to the highest dry density
Geo Group Northwest, Inc.
May 28, 1998 G-0907
Proposed Single Family Residence Page 7
for a given compaction effort.
Due to its silt content, some of the existing loose fill soils are. considered to be moisture sensitive
and should not be used as fill material during wet weather conditions. During dry weather, any
compactable non -organic soil meeting the above maximum size criteria may be used as structural
fill, provided the material is near the optimum moisture content for compaction purposes.
Structural fill should be placed in thin horizontal lifts not exceeding ten inches in loose thickness.
Structural fill under driveways, patios and sidewalks should be compacted to at least 90 percent
of maximum density, with the exception of the upper twelve (12) inches. The top twelve (12)
inches should be compacted to at least 95 percent maximum density, as determined by ASTM
Test Designation D-1557-91 (Modified Proctor).
We recommend that Geo Group Northwest, Inc. be retained to evaluate the suitability of
structural fill material and to monitor the compaction requirement during construction for quality
assurance of the earthwork.
6.3 Spread Footing Foundations
It is our opinion that the eastern half of the house can be supported by conventional spread
footings bearing on the dense undisturbed native soils or compacted structural fill bearing on the
dense undisturbed native soils. The conventional spread footing foundations can be designed as
follows:
- Allowable bearing pressure, including all dead and live loads
on undisturbed dense gravelly sand = 2,000 psf
on compacted structural fill = 2,000 psf
- Minimum depth to bottom of perimeter footing
below adjacent final exterior grade = 18 inches
- Minimum depth to bottom of interior footings
below top of floor slab = 18 inches
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May 28, 1998 G-0907
Proposed Single Family Residence Page 8
- Minimum width of wall footings = 16 inches
- Minimum lateral dimension of column footings = 24 inches
- Estimated post -construction settlement = 1/4 inch
- Estimated post -construction differential
settlement; across building width = 1/4 inch
A one-third increase in the above allowable bearing pressures can be used when considering short-
term transitory wind or seismic loads.
Lateral loads can also be resisted by friction between the foundation and the supporting
compacted fill subgrade or by passive earth pressure acting on the buried portions of the
foundations. For the latter, the foundations must be poured "neat" against the existing
undisturbed soil or backfilled with a compacted fill meeting the requirements of structural fill.
Structural fill requirements can be found in Section 6.2 - Site Preparation and General
Earthwork. It is our professional opinion that the following parameters can be used:
- Passive pressure
- Coefficient of friction
6.4 Augered Concrete Piles
= 300 pcf equivalent fluid weight
= 0.30
We recommend that the western half of the proposed house be supported on a foundation system
consisting of augered concrete piles. This recommendation is based on the loose soil conditions
encountered in Boring B-2 down to a depth of 7 feet below the ground surface.
The pile foundation should penetrate through the loose to medium dense zones, with a minimum
embedment of five feet into the very dense gravelly SAND below. We estimate that the total
length of each pile to be about 12 feet below the ground surface.
We recommend that the diameter of the augered hole have a minimum diameter of 14 inches. For
augered reinforced concrete piles of 14 and 16 inches in diameter embedded into very dense
Geo Group Northwest, Inc.
May 28, 1998
Family Residence
G-0907
Page 9
gravelly SAND with a minimum of 5 feet embedment, the following allowable bearing capacities
may be used:
Pile Diameter
14
16
Pile Embedment
(Feet)
5
5
Allowable Bearing
(Tons)
10
12
Allowable Uplift
(Tons)
5
0
Note: Pile Embedment Length based on the embedment depth below the top of the very, dense
gravelly SAND.
No reduction in pile capacities is required if the pile spacing is at least three times the pile
diameter. A one-third increase in the above allowable pile capacities can be used when
considering short-term transitory wind or seismic loads.
Lateral loads can also be resisted by using battered piles or by the passive earth pressures acting
on grade beams. To fully mobilize the passive pressure resistance, the grade beams must be
poured "neat" against compacted fill. Our recommended allowable passive soil pressure for
lateral resistance is 300 pcf equivalent fluid weight. A coefficient of friction of 0.30 may be used
between the subgrade and the grade beam.
We estimate that the maximum total post -construction settlement should be one -quarter (1/4) inch
or less, and the differential settlement across the building width should be one -quarter (1/4) inch
or less.
The performance of piles depends on how and to what bearing stratum the piles are installed.
Since a completed pile in the ground cannot be observed, it is critical that judgement and
experience be used as a basis for determining the embedment length and acceptability of a pile.
Therefore, we recommend that Geo Group Northwest, Inc. be retained to monitor the pile
installation operation, collect and interpret installation data and verify suitable bearing stratum.
We also suggest that the contractor's equipment and installation procedure be reviewed by Geo
Group Northwest, Inc. prior to pile installation to help mitigate problems which may delay work
progress. A structural engineer should be retained to design the reinforced augered concrete
Geo Group Northwest, Inc.
May 28, 1998 G-0907
Proposed Single Family Residence Page 10
piles.
6.5 Slab -on -Grade Floors
Based on the encountered site conditions, we anticipate that the house will have supported floors,
if slab on -grade floors are used, the slab -on -grade floors may bear on the. dense undisturbed soil
below the site, or on compacted structural fill, placed above the dense natural soils, compacted as
specified in Section 6.2 - Site Preparation and General Earthwork of this report. All loose
soil should be removed, or replaced with engineered structural fill.
To avoid moisture build-up on the subgrade, slab -on -grade floors should be placed on a capillary
break, which is in turn placed on the prepared subgrade. The capillary break can consist of a
minimum of six (6) inches thick layer of free -draining gravel containing no more than five (5)
percent finer than No. 4 sieve. A vapor barrier, such as a 6-mil plastic membrane, is
recommended to be placed over the capillary break beneath the slab to reduce water vapor
transmission through the slab. Two to four inches of sand may be placed over the barrier
membrane for protection during construction.
In preparing the subgrade, native soils disturbed by construction activity should either be
recompacted, or excavated and replaced with compacted, well -draining, structural fill or crushed
rock. Prior to placing the capillary break, the barrier membrane and the concrete for slabs -on -
grade, we recommend the subgrade be proof, rolled with a piece of heavy construction equipment,
such as a fully loaded dump truck. Any soft spots or disturbed areas thus detected should be
recompacted or excavated, replaced and compacted as described above.
If groundwater seepage is encountered in the foundation slab area, we recommend that a
geotextile fabric, such as Mirafi 500X, or equivalent, be placed on the wet subgrade, above which
a minimum six (6) inch layer of one and a half (1.5) inch minus gravel, or 2-inch crushed rock, no
fines, be used as a capillary break. This will also eliminate the need for the 6-mil plastic
membrane.
6.6 Permanent Basement and Conventional Retaining Walls
Permanent basement walls restrained horizontally on top are considered unyielding and should be
Geo Group Northwest, Inc.
May 28, 1998 G-0907
Proposed Single Family Residence - Page 11
designed for a lateral soil pressure under the at -rest condition; while conventional reinforced
concrete walls free to rotate on top should be designed for a active lateral soil pressure.
Active Earth Pressure
Conventional reinforced concrete walls that are designed to yield an amount equal to 0.002
times the wall height, should be designed to resist the lateral earth pressure imposed by an
equivalent fluid with a unit weight of:
• 3 5 pcf for level backfill behind yielding retaining walls;
At -Rest Earth Pressure
Walls supported horizontally by floor slabs are considered unyielding and should be designed
for lateral soil pressure under the at -rest condition. The design lateral soil pressure should
have an equivalent fluid pressure of:
• 60 pcf for level ground behind permanent unyielding retaining walls;
Passive Earth Pressure and Base Friction
The available passive earth pressure that can be mobilized to resist lateral forces may be
assumed to be equal to 300 pcf equivalent fluid weight for both undisturbed soils and
engineered structural backfill.
The base friction that can be generated between concrete and undisturbed bearing soils or
engineered structural backfill may be based on an assumed 0.30 friction coefficient.
We recommend that a vertical drain mat, Miradrain 6000 or equivalent, be used to facilitate
drainage behind permanent concrete basement or conventional retaining walls. The drain mat
core is placed against the basement wall with the filter fabric side facing the backfill. The drain
mat extends from the finished surface grade, down to the footing drain pipe. A minimum of 18
inches of clean, free -draining, washed rock, crushed rock, or pea gravel should be placed in the
F. bottom of the footing trench. With the above exceptions, perimeter foundation drainage
recommendations and installation procedures are in the - Footing and Wall Drains section of this
report. Please also refer to Plate 8 - Typical Basement Wall Backfill and Drainage Details.
If vertical drain mats are incorporated into the design, we recommend using the existing native
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May 28, 1998 G-0907
Proposed Single Family Residence Page 12
soils as structural backfill behind the walls, provided the native material can achieve the specified
compaction. If the native soil cannot achieve the specified compaction, then we recommend
placing a free draining granular backfill material.
Alternatively, to prevent buildup of hydrostatic pressure behind permanent concrete basement or
conventional retaining walls, a granular, free draining structural backfill material can be placed
i within a horizontal distance of 18 inches of the wall, in place of vertical drain mats. We
recommend using a clean, granular, free -draining, structural fill material, free of organic or other
deleterious substances, such as pea gravel, or washed rock, containing no more than five percent
i fines passing the No. 200 sieve based on the fraction of material passing the No. 4 sieve. The
( free -draining granular material should surround the wall subdrain system as described in the
footing drain section of this report. The top twelve (12) inches of the fill should consist of
compacted and relatively impermeable soil. This cap material can be separated from the
underlying more granular drainage material by a layer of building paper or visqueen. The surface
should be sloped to drain away from the building wall. Alternatively; the surface can be sealed
with asphalt or concrete paving.
Where backfill material behind permanent concrete basement or conventional retaining walls is not
supporting slabs, or structural loads, the backfill should be compacted to 90 percent of the
maximum dry density determined by ASTM D 1557-91 (Modified Proctor Method). The top 12-
inches should be compacted to 95 percent of the maximum dry density.
The backfill in areas adjacent to basement or conventional retaining walls should be compacted
with hand held equipment or a hoepack. Heavy compacting machines should not be allowed
within a horizontal distance to the wall equivalent to one half the wall height, unless the walls are
designed with the added surcharge.
6.7 Excavations and Slopes
Under no circumstances should temporary excavation slopes be greater than the limits specified in
local, state and national government safety regulations. Temporary cuts greater than four feet in
height should be sloped at an inclination no steeper than 1H:1V (Horizontal Vertical). A
geotechnical engineer or geologist should determine the type of soil encountered in the excavation
and determine the safe inclination of the excavation.
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May 28, 1998 G-0967
Proposed Single Family Residence Page 13
Surface runoff should not be allowed to flow uncontrolled over the top of slopes into the
excavated area. During wet weather exposed cut slopes should be covered with plastic sheets
during construction to minimize erosion.
To improve the surficial stability of the slope especially when doing excavation, we recommend
that the existing slope vegetation be maintained. Waste debris, such as lawn clippings and tree
limbs should not be discarded on the slope.
All permanently exposed slopes should be planted with an appropriate species of vegetation to
reduce erosion and improve the stability of the surficial layer of soil. Geo Group Northwest, Inc.
should be consulted if changes to the above plans are contemplated.
6.8 Drainage
6.8.1 Surface Drainage
The finished ground of the site should be graded such that surface water is directed away from the
structure and off the site. Water should not be allowed to stand in any area where footings, slabs,
parking lot or pavements are to be constructed. During construction, loose surfaces should be
sealed at night by compacting the surface to reduce the potential for moisture infiltration into the
soils. Final site grades should allow drainage away from buildings. We suggest that the ground
be sloped at a gradient of three (3) percent for a distance of at least ten feet away from buildings
except in areas that are to be paved.
6.8.2 Footing and Wall Drains
We recommend that drains be installed around the foundation perimeters and behind concrete
retaining walls. The drains should consist of a four (4) inch minimum diameter, perforated or
slotted, rigid drain pipe laid at or just below the invert of the footing with a gradient sufficient to
generate flow (see, Plate 9 - Typical Footing Subdrain). The drain line should be bedded on,
surrounded by, and covered with a free -draining rock, pea gravel, or other free -draining granular
material.
Geo Group Northwest, Inc.
c.
' May 28, 1998 G-0907
Proposed Single Family Residence Page 14
Once the drains are installed, the excavation behind foundation walls should be backfilled with a
compacted structural fill material. For structural backfill criteria behind walls, please refer to
Section 6.5 - Permanent Basement and Conventional Retaining Walls. The surface should
be sloped to drain away from the building wall or sealed with asphalt or concrete paving.
Under no circumstances should roof downspout drain lines be connected directly to the footing
drain system. All roof downspouts must be separately tightlined to discharge into the storm water
collection system. We recommend that sufficient cleanouts be installed at strategic locations to
allow for periodic maintenance of the footing drains and downspout tightline systems.
6.9 Driveway Area
It is anticipated that the driveway area is to support passenger cars and light trucks only, we
recommend the pavement design to consist of the following:
Two inches of Asphalt Concrete (AC) over four inches of Crushed Rock base (CRB) material,
The adequacy of site pavements is strictly related to the condition of the underlying subgrade. If
this is inadequate, no matter what pavement section is constructed, settlement or movement of the
subgrade will be reflected up through the paving. In order to avoid this situation, we recommend
the subgrade be treated and prepared as described in Section 6.2 - Site Preparation and
General Earthwork of this report. At least the top twelve (12) inches of the subgrade should be
compacted to 95 percent of the maximum dry density (per ASTM D-1557-91). It is possible that
some localized areas of soft, wet or unstable subgrade may still exist after this process. If so, they
may require overexcavation of the unsuitable materials and their replacement with a compacted
structural fill or a crushed rock.
7.0 LIMITATIONS
This project has been prepared for the specific application to this site for the exclusive use of Ms.
Elizabeth Nelson, and her representatives. We recommend that this report in its entirety be
included in the project contract documents for use by the contractor.
Geo Group Northwest, Inc.
J I
t
v ` '
' May 28, 1998 G-0907
Proposed Single Family Residence Page 15
Our findings, conclusions and recommendations stated herein are based on site observations,
subsurface conditions encountered in our field exploration, our experience and engineering
judgement. The conclusions and recommendations are professional opinions derived in a manner
consistent with the level of care and skill ordinarily exercised by other members of the profession
currently practicing under similar conditions in this area. No warranty, expressed or implied is
made.
Soil and groundwater conditions described herein may vary from those actually encountered
during construction. The nature and extent of such variations may not become evident until
construction. If variations appear then, Geo Group Northwest, Inc. should be requested to re-
evaluate the recommendations in this report and to verify or modify them in writing prior to
proceeding with construction.
8.0 ADDITIONAL SERVICES
We recommend that Geo Group Northwest, Inc. be retained to perform a general review of the
final design. This is to verify that our recommendations included herein are properly interpreted
and implemented in the design and in the construction documents.
We also recommend that Geo Group Northwest, Inc. be retained to provide monitoring and
testing services for geotechnically related work during construction. This is to observe
1 compliance with the design concepts, specifications or recommendations and to allow design
changes in the event subsurface conditions differ from those anticipated prior to and during the
construction.
Geo Group Northwest, Inc.
May 28, 1998 G-0907 .
Proposed Single Family Residence Page 16
Respectfully submitted
GEO GROUP NORTHWEST, INC.
Linjung "Steve" Hou, P.E. a� ��o�w'o�
Geotechmcal Engineer
T
20114
2� 's�ONAL
EXIMMS
William Chang, P.E.
Principal
Geo Group Northwest, Inc.
r +
BROWNS /
BAY
FREDERICK
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KAH
VICINITY MAP
Group Northwest, Inc. ELIZABETH NELSON RESIDENCE
Geotechnical Engineers, Geologists, & 18318 OLYMPIC VIEW DRIVE
Environmental Scientists EDMONDS, WASHINGTON
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LEGEND OF SG.— CLASSIFICATION AND PENEI."TION TEST
UNIFIED SOIL CLASSIFICATION SYSTEM (USCS)
LABORATORY
GROUP
MAJOR DIVISION
TYPICAL DESCRIPTION
CLASSIFICATION
SYMBOL
CRITERIA
WELL GRADED GRAVELS, GRAVEL -SAND
Cu = (D601 D10) greater than 4
CLEAN
C'W
MIXTURE, LITTLE OR NO FINES
DETERMINE
Cc = (D30 ' D30 / D101 D60) between 1 and 3
GRAVELS
PERCENTAGES
GP
POORLY GRADED GRAVELS, AND GRAVEL -SAND
NOT MEETING ABOVE REQUIREMENTS
GRAVELS
Pittle or no
OF GRAVEL AND
fines)
MIXTURES LITTLE OR NO FINES
SAND FROM
(More Than Half
GRAIN SIZE
ATTERBERG LIMITS BELOW
Coarse Grains
DISTRIBUTION
COARSE
Larger Than No.
DIRTY
GM
SILTY GRAVELS, GRAVEL -SAND -SILT MIXTURES
CURVE.
CONTENT
"A" LINE.
GRAINED
4 Sieve)
GRAVELS
OF FINES
or P.I. LESS THAN 4
SOILS
COARSE GRAINED
EXCEEDS
ATTERBERG LIMITS ABOVE
(with some
CLAYEY GRAVELS, GRAVEL -SAND -CLAY
SOILS ARE
12%
"A' LINE.
fines)
GC
MIXTURES
CLASSIFIED AS
or P.I. MORE THAN 7
FOLLOWS:
WELL GRADED SANDS, GRAVELLY SANDS,
Cu = (D60 / D10) greater than 6
More Than Half
CLEAN
SW
L1fTLE OR NO FINES
< 5%Fine Grained:
Cc = (D30 ' D30 / D10 / D60) between 1 and 3
by Weight
SANDS
GW, GP, SW. SP
SP
POORLY GRADED SANDS, GRAVELLY SANDS,
NOT MEETING ABOVE REQUIREMENTS
Larger Than No.
200 Sieve
SANDS
(little or no
> 12% Fine
(More Than Halt
fines)
LITTLE OR NO FINES
Grained.
Coarse Grains
GM, GC, SM, SC.
ATTERBERG LIMITS BELOW
Smaller Than
DIRTY
SM
SILTY SANDS, SAND -SILT MIXTURES
5 to 12% Fine
CONTENT
'A" LINE
No. 4 Sieve)
SANDS
OF FINES
with P.I. LESS THAN 4
Grained. use dual
symbols.
EXCEEDS
ATTERBERG LIMITS ABOVE
(w th some
SC
CLAYEY SANDS, SAND -CLAY MIXTURES
12%
"A" LINE
fines)
with P.I. MORE THAN 7
SILTS
Liquid Limit
INORGANIC SILTS. ROCK FLOUR, SANDY SILTS
(Below A -Line
< 50%
ML
OF SLIGHT PLASTICITY
00
1 1 PLASTICITY CHART
A -line
on Plasticity
---- --
I FOR SOIL PASSING
Chart, Negligible
Liqud LimA
INORGANIC SILTS, MICACEOUS OR
FINE-GRAINED
Organic)
> 50%
I MH
DIATOMACEOUS, FINE SANDY OR SILTY SOIL I
so
__11-1I NO. 40 SIEVE
SOILS
o i
Cl-Or0
INORGANIC CLAYS OF LOW PLASTICITY,
X 40
CLAYS
Liquid Limo . CL
GRAVELLY, SANDY, OR SILTY CLAYS, CLEAN
tL
(Above A -Line on
` 30%
I CLAYS
Z
'.'.,T
i
Placbcrty Chart.
- ---
- --
> 30---^---- - -
Lipwd Limn I
INORGANIC CLAYS OF HIGH PLASTICITY, FAT
----�--
L or
L
--�---�---i-------
More Than Half
Negligible
i e
I
I j'
aniC
9 )
, 50% CH
CLAYS
by Weight
H
N `0
Smaller Than
QQ !
I
'
No 200 Sieve
ORGANIC
Liquid Limn
ORGANIC SILTS AND ORGANIC SILTY CLAYS OF
a
H 0r DH
SILTS & CLAYS
` 50%
OL
LOW PLASTICITY
I10
(Below A -Line
4
r Vj
on Placticity
Liquid Limit
j OH
ORGANIC CLAYS OF HIGH PLASTICITY
l-OL
0
Chart)
> 50%
0 10 20 30 40 50 60 70 80 90 100
LIQUID LIMIT (%)
HIGHLY
ORGANIC SOILS
Pt
PEAT AND OTHER HIGHLY ORGANIC SOILS
SOIL PARTICLE SIZE
GENERAL GUIDANCE OF SOIL ENGINEERING PROPERTIES
FROM STANDARD PENETRATION TEST (SPT)
U.S. STANDARD SIEVE
Passing
Retained
SANDY SOILS
SILTY & CLAYEY SOILS
FRACTION
Sieve
Size
Sieve
Size
Blow
Relative
Friction
Blow
Unconfined
(mm)
(mm)
Counts
N
Density
%
Angle
0, degree
Description
Counts
N
Strength
qu, tsf
Description
SILT I CLAY
#200
0.075 '
SAND
0-4
0 -15
Very Loose
< 2
< 0.25
Very soft
FINE
940
0.425
#200
&075
4 - 10
15 - 35
26 - 30
Loose
2.4
0.25 - 0 50
Soft
MEDIUM
#10
0
940
0.425
10 - 30
35 - 65
28 - 35
Medium Dense
4.8
0 50 - 1.00
Medium Stiff
COURSE
#4
4.75
1 #10 -
2
30-50
> 50
65 - 85
85 - 100
35 - 42
38 - 46
Dense
Very Dense
8 - 15
15 - 30
1,00 - 2,00
2.00 - 4.00
Stiff
Very Stiff
GRAVEL
1
FINE
19
#4
4.75
> 30
> 4.00
Hard
Group Northwest, Inc.
COURSE
, 76
19
COBBLES
76mmto203mm
BOULDERS
> 203 mm
Geotechnical Engineers, Geologists, &
Environmental Scientists
ROCK
FRAGMENTS
76 mm
13240 NE 20M Street, Suite 12 Bellevue, WA 98005
Phone (206) 649-8757 Fax (206) 649-8758
[{
PLATE
ROCK
>0 76 cubic meter in volume
' BORING NO. B-1
Logged By: SH Date Drilled: 4/7/98 Surface Elev. 189 feet
Depth
SAMPLE
SPT
slows
SPT (N)
slows
Water
Content
Other Tests b
uses
Soil Description
per
per
%
Comments
Type
No.
ft.
6_inches
foot
SP/
Brown SAND with gravel and trace of silt, medium dense, moist
T
S1
2,5,7
12
7.9
SM
Drill rig stuck ® 2.5 feet due to rock, added water in hole to ease drilling
1
I
S2
10,11,35
46
5.9
Brown/gray gravelly SAND with pebble and trace of silt, very dense, damp
5
SP/
to moist.
SM
T
S3
30,32,33
65
5.9
10
Note:
Total depth = 6.5 feet.
There was no water seepage encountered.
15
20
25
30
35
40
Using 6"O.D portable rig, standard 140 lbs
hammer and 2"O.D. split- sampler
=
BORING LOG
ELIZABETH NELSON RESIDENCE
O wes nic.
tM
_!!roup
18318 OLYMPIC VEIW DRIVE
_ Geotechnical Engineers, Geologists, &
EDMONDS, WASHINGTON
Environmental Scientists
DATE 4/22/98
JOB NO. G-0907
PLATE 5
0
" BO NG NO. B-2
Logged By: SH Date Drilled: 4/71998 Surface Elev. 180 feet
Depthluscsl
Soil Description
SAMPLE
SPT
Blows
SPT (N)
Blows
Water
Content
Other Tests d
per
per
%
Comments
Type
No.
ft
6-inches
foot
SM
Brown SAND with some silt and gravel, loose, moist (Fill)
T
S 1
11.9
Drilling gets slower at 4.5 feet
1
IS2
1,2,1
3
16.0
5
SM/
light brown SAND with some gravel and silt, medium dense, moist
T
S3
3,4,10
14
8.7
SP
at 7 to 8 feet, drill rig gets stuck, added water to ease drilling
1
----
------------------------------------------------
Brown gravelly SAND with pebble and trace of sift, dense to very dense,
ISp/
S4
15,21,24
45
11.5
10
SM
moist
I35
13,13,17
30
16.4
IS6
15,50/3"
50/3"
12.6
15
Note:
Total depth = 13.5 feet.
20
There was no water seepage encountered.
25
30
35
40
Using 6"0.D portable rig, standard 140 lbs
hammer and 2"O.D. split- sampler
—
BORING LOG
Group Northwest, Inc.
ELIZABETH NELSON RESIDENCE
18318 OLYMPIC VIEW DRIVE
_ Geotechnical Engineers, Geologists, 3
EDMONDS, WASHINGTON
Environmental Scientists
DATE 4/22/98
1 JOB NO. G-0907
IPLATE 6
� w
BORING NO. B-3
Logged By: SH Date Drilled: 4/7/98 Surface Elev. 189 feet +I-
Depth SPT I SPT (M Water
USCS Soil Description SAMPLE Blows Blows content . Other Tests d
ft. per Per % Comments
Type
No.
64nches
foot
I
S1
4,7,5
12
no
SP/
Brown SAND with gravel and trace of silt medium dense, moist
recover
SM
hard to drill @ 2 feet due to rock
T
S2
9,9,11
2p
9.9
s_..
.-... _. -.... _.... _._. _...
_ — _....-............. _..., _........_
1
SP/
�. _
Light brown gravelly SAND with pebble and trace of silt, very dense, damp
T
14,17,39
SM
to moist.
S3
S6
11.1
10
Note:
Total depth = 6.5 feet.
15 There was no water seepage encountered.
20
25
30
35 J
40 1 1
Using 6"O.D portable rig, standard 140 lbs
hammer and 2"O.D. split- sampler
roup
Geotechnical Engineers, Geologists, R
Environmental Scientists
DATE
BORING LOG
ELIZABETH NELSON RESIDENCE
18318 OLYMPIC VEIW DRIVE
EDMONDS, WASHINGTON
4/22/9R I JOB NO. G-0907
PLATE 7
w
Basement
Nall
Slope to drain
Vertical Drain Mat
r in 6000
adra (M�
:::•:.:;:::::;:;:::::•:•:.:::•::.:: E:::`�:�.'„y•.I+� orequal)
Relative
Impermeable
LUSABLE)
ILL
Free draining material,
(Washed rock or Crushed ((IFrock)Geoteztile
(miraft 140 NE:or equal) ... .
4 or 6 inch diameter 'F00��NG:
slotted or perforated
PVC pipe
NOT TO SCALE
NOTES:
1.) Do not replace rigid PVC pipe with flexible corrugated plastic pipe.
2.) Perforated or slotted PVC pipe should be tight jointed and laid with
perforations or slots down, with positive gradient to discharge.
3.) Do not connect roof downspout drains into the footing drain lines.
4.) Backfill should be compacted to 90% of maximum dry density based on
Modified Proctor. The top one foot should be compacted to 95% of
maximum dry density if backfill is to support sidewalks, driveway, etc.
TYPICAL BASEMENT WALL BACKFIL,L
Group Northwest, Inc. AND DRAINAGE DETAIL
Geotechnical Engineers, Geologists, b
Environmental Scientists
SCALE NONE I DATE 5/7/98 I MADE SH I CHKD WC I JOB NO. G-907 I PLATE 8
BACKFILL WITH COMPACTED
NATIVE, RELATIVE
IMPERMEABLE SOIL
GEOTEXTILE FILTER FABRIC,
MIRAFI 140 NL, AMOCO 4535,
4545, OR EQUAL
FREE DRAINING BACKFILL�
CONSISTING OF WASHED
ROCK OR CRUSHED ROCK
MINIMUM 4 INCH DIAMETER
PERFORATED PVC PIPE
WITH POSITIVE GRADIENT
TO DISCHARGE
6"to 12
y
NOT TO SCALE
NOTES:
1.) Do not replace rigid PVC pipe with flexible corrugated plastic pipe.
2.) Perforated'or slotted PVC pipe should be tight jointed and laid with
perforations or slots down, with positive gradient to discharge.
3.) Do not connect roof downspout drains into the footing drain lines.
Group Northwest, Inc.
Geotechnical Engineers, Geologists, 3
""Inump- Environmental Scientists
TYPICAL FOOTING DRAIN
I SCALE NONE I DATE 5/7/98 I MADE SH
CHKD WC I JOB NO. G-0907 ( PLATE 9
CA FILE NO.
Critical Areas Checklist
--------------------------------------------------------------
Site Information (soils/topography/hydrology/vegetation)
1. Site Address/ Location: L�/�'1 %lam MEOW EDN /Q�S fffdA O
2. Property Tax Account Number:(
3. Approximate Site Size (acres or square feet):
4. Is this site currently developed? Vyes; —
If yes; how is site developed?
00
no.
5. Describe the general site topography. Check all that apply. v
e" PERMIT Wui" S y
7� Flat: less than 5-feet elevation change over entire site.
_ Rolling: slopes on site generally less than 15% (a vertical rise of 10-feet over a
horizontal distance of 66-feet).
jHilly: slopes present on site of more than 15% and less than 30% ( a vertical
rise of 10-feet over a horizontal distance of 33 to 66-feet).
Steep: grades of greater than 30% present on site (a vertical rise of 10-feet over
a horizontal distance of less than 33-feet).
Other (please describe):
6. Site contains areas of year-round standing water: J1) 0 ; Approx. Depth:
7. Site contains areas of seasonal standing water: AL ; Approx. Depth:
What season(s) of the year?
8. Site is in the floodway-_,A/0 floodplain of a water course.
9. Site contains a cr ek or an area where water flows across the grounds surface? Flows are
year-round? AJ Flows are seasonal? (What time of year? ).
10. Site is primarily: forested ; meadow ; shrubs ; mixed ;
urban landscaped (lawn,shrubs etc)
11. Obvious wetland is present on site:
----------------------- ------------- --------------- For City Staff Use Only -------- ---------------------------------------- --
1. Site is Zoned? %% 5 — / Z-
2. SCS mapped soil type(s)? /�P f C�(�i�'1l- S,�p� �,/C _ 7p6c%
3. Wetland inventory or C.A. map indicates wetland present on site? 9_'
4. Critical Areas inventoryor C.A. map indicates Critical Area on site?
5. Site within designated earth subsidence;landslide hazard area?
6. Site designated on the Environmentally, Sensitive Areas Map? /✓O
DETERMINATION
City of Edmonds
Critical Areas Checklist
'nC. 189'-'
The Critical Areas Checklist contained
on this form is to be filled out by any
person preparing a Development Permit
Application for the City of Edmonds
prior to his/her submittal of a
development permit to the City.
The purpose of the Checklist is to enable
City staff to determine whether any
potential Critical Areas are or may be
present on the subject property. The
information needed to complete the
Checklist should be easily available
from observations of the site or data
available at City Hall (Critical Areas
inventories, maps, or soil surveys).
An applicant, or his/her representative,
must fill out the checklist, sign and date
it, and submit it to the City. The City
will revi 2w the checklist, make a
precursory site visit, and make a
determination of the subsequent steps
necessary to complete a development
permit application.
With a signed copy of this form, the
applicant should also submit a vicinity
map or plot plan for individual lots of
the parcel with enough detail that City
staff can find and identify the subject
parcel(s). In addition, the applicant
shall include other pertinent
information (e.g. site plan, topography
map, etc.) or studies in conjunction
with this Checklist to assist staff in
completing their preliminary
assessment of the site.
1 have completed the attached Critical Area Checklist and attest that the answers
provided are factual, to the best of my knowledge (fill out the appropriate column
below).
Owner/ Applicant:
Nan
Str Address
City, State, ZIP Phone
*Siature Date
Applicant Representative:
Name
Street Address
City, State, ZIP Phone
Signature
Date
A -
the 1B9I )
CITY OF EDMONDS BARBARAFAHEY
121 5TH AVENUE NORTH EDMONDS, WA 98020 (425) 771-0220 •FAX (425) 771-0221 MAYOR
COMMUNITY SERVICES DEPARTMENT
Public Works • Planning/Building • Parks and Recreation • Engineering • Wastewater Treatment Plant
October 15, 1997
Galen D. Holmquist
Paradise Construction
23632 Hwy. 99, F-311
Edmonds, WA 98026
Dear Mr. Holmquist:
This letter is in response to your letter dated October 7, 1997, regarding Elizabeth Nelson's home
at 18318 Olympic View Drive.
You state that you understand that this house is nonconforming, per Edmonds ordinance
17.40.020. This is true, in that our Critical Areas ordinance, Edmonds Community Development
Code (ECDC) Chapter 20.15B was enacted since the house was built. This chapter seeks to
protect the public from losses due to steep slope failure and other hazards of critical areas.
ECDC Section 20.15B.110 requires a 50 foot buffer from the top or toe of a steep slope, unless a
geotechnical engineer can convince the Planning division that reducing the buffer to 10 feet
would not have any adverse impact. A building setback of 15 feet is required to this buffer by
ECDC Section 20.15B.080.C., for a total setback to the building of between 25 feet and 65 feet.
Although no critical areas study has yet been submitted to determine the actual top of slope, as
required by Critical Areas Determination CA-97-90, a top of slope has been indicated on the site
plan in building permit application PC-97-284. The west addition appears to be 23 feet from the
top of the slope, and the portion of the house further east appears to be 38 feet to the top of the
slope at its closest point. To determine the actual distances we will need a critical areas study
done by a licensed land surveyor. If the surveyor determines that the setback from the top of the
slope to the house is less than 25 feet, that portion of the structure within 25 feet will be
considered nonconforming. If a geotechnical engineer submits a report stating that reducing the
buffer to 10 feet will not result in any adverse impact, then the portion of the house further than
25 feet will be in conformance with the code. If a geotechnical engineer feels that more of a
buffer is needed, then the portion of the structure not meeting the buffer and building setback
required will also be considered nonconforming.
The value of the home, according to our Metroscan records is $64,300. ECDC 17.40.020 allows
nonconforming buildings to be maintained and continued, so long as the degree of
nonconformity is increased. ECDC 17.40.020 further specifies that in the event that a
nonconforming building is destroyed or damaged in an amount equal to 50 percent or more of its
replacement cost at the time of destruction, said building shall not be reconstructed except in
conformance with the provisions of the ECDC. It follows that any restoration of the building
® Incorporated August 11, 1890 •
Sister Cities International — Hekinan, Japan
Galen D. Holmquist
October 15, 1997
Page 2
which costs $32,150 or more will have to be done in conformance with the provisions of the
ECDC.
The only portion of the building which is affected by the nonconforming provisions is within the
area that is in the required steep slope buffer and building setback. If the building is torn down
to the foundation, all of the building will have to be in conformance with the required critical
areas buffers and setbacks. If the west addition will not need any remodeling which will impact
the critical areas, ECDC Section 20.15B.040.A.2 would allow the remodeling. I would interpret
this to mean reroofing, residing, or interior work. However, if the framing has to, be replaced, it
would appear to be major work with potential adverse impacts, and any replacement would have
to meet the required setbacks.
You also asked, in your facsimile today, about the existing permits and plans. After checking
with the Building Official, I understand that the permit has had correction notices sent, and we
are awaiting information to be submitted. It will continue in that status until corrections are
submitted. If the owner wishes to withdraw their permit application upon receipt of this letter,
the city would then consider the plans null and void.
If you have any questions, please call me at (425) 771-0220.
Sincerely,
Me L w����
g ru ell
Planner
cc: File PC-97-284