20070925115418.pdfOV Ebro City of Edmonds
PLAN REVIEW COMMENTS
BUILDING DIVISION
Fsr. ia9° (425) 771-0220
DATE: September 25, 2007
TO: Tiffany Bui
FAX: 425-640-5830
FROM: Ann Bullis, Assistant Building Official %��
RE: Revision to Permit #2006-0556
Project: Bui ---- Single Family Residence
Project Address: 16105 75th Place West
During re -review of the revised plans for the above noted project, it was found that the following
information, clarifications or changes are needed. Provide written responses to each comment and
where changes can be found on the plans. Please resubmit to Theresa Umbaugh, Permit
Coordinator.
1. Previous item 2: Structural calculations are required for the rockery. Rockery construction
details and calculations must be stamped and signed by the Structural Engineer of Record.
Details must be cross-referenced to the site plans. See enclosed City Rockery Handout which
has specific requirements for the Earth Subsidence Landslide Hazard Area. Also, on City
Standard Detail E8.9, the Earth Subsidence Landslide Hazard Area is an exception noted in Item
4, requiring the rockery to be designed, including calculations.
2. Provide a letter from the Geotechnical Engineer specifically noting which rockeries were
inspected in report dated 7/12/07 and address Special Inspection Requirements on page 4 of the
City Rockery Handout. The letter must also address Item 8 of Submittal Requirements on page
1 of the City Rockery Handout as well as Item 8 on page 6 of the handout.
Once the above information is received making the revision submittal complete, the City will send
the revised plans and calculations out for peer review.
#B63
City of edmonds
development information
to C.. 1 o"
Rockery
Permit Submittal Requirements
PERMIT REQUIRED: A permit is required for Rockery construction unless specifically
exempted as described in this handout. Any Rockery located in a
Critical Area -or in the mapped Earth Subsidence Landslide Hazard
Area (ESLHA) of North Edmonds, must obtain a permit regardless
of height, mass or length.
CODES: International Building Code (Current Edition)
WSDOT/APWA Standard Specifications for Road, Bridge &
Municipal Construction (Current Edition)
ECDC Chapters 18.30 & 18.40.020
ECDC Chapters 19.00 & 19.10
ECDC Chapter 23.80
City Ordinance #2916
FEE: Permit Review fee $265 plus $15 City surcharge
Permit Inspection fee $50 per required City Inspection
*Some projects may require Development Project Peer Review;
when required, fees are charged at $110 plus the cost of Peer
Review
SUBMITTAL REQUIREMENTS: (See Page 5)
1. A Critical Areas Determination, issued by the Planning Division (See Handout #P20)
2. Soils Investigation or Soils Report — Three (3) copies, stamped and signed by a Washington
State licensed Geotechnical Engineer or Engineering Geologist
3_ Grading Plan - Three (3) copies, with yardage calculations
4. Plot Plan - Three (3) copies, scaled 1"=20'
5. Rockery Section and Elevation Views - Two (2) copies, stamped and signed by a
Washington State licensed Engineer
6. Rockery Design Calculations - Two (2) copies, stamped and signed by a Washington State
licensed Engineer
7. Erosion and Sedimentation Control Pian - Three (3) copies (See Handout #E72)
8. For Rockeries in Critical Areas designated as geologically hazardous areas or, in the mapped
ESLHA, a letter from a Washington State licensed Geotechnical Engineer addressing the
criteria of ECDC Chapter 23.80.070.
L_1TEMMUiMIN&HANDOUT ICODES 20031ROCIERY B63.DOC Page I of 9
Revised 8106
INTRODUCTION
The City of Edmonds does not consider Rockeries to be retaining walls. Different and more
restrictive structural standards apply to retaining wall construction. (See Handout 4IB62)
Rockery construction is a craft and depends largely on the skill and experience of the licensed
contractor performing the work. Rockeries have long been used for erosion control and as
landscaping features. The long term stability, durability and safety of rockeries are dependant on
the use of proper construction methods and materials.
DEFINITIONS (See attached Engineering Standard Details E8.9 and E8.10)
Rockery Height. For permitting purposes, Rockery Height is defined as the height measured
vertically from the finished grade at the toe of the rockery to the highest point of the uppermost
rock.
Setback Area Height. For setback purposes, Rockery Setback Area Height is defined as the
height measured vertically from the original grade to the highest point of the uppermost rock.
PROHIBITED ROCKERIES
• Rockeries are not permitted to encroach or be located in, on, or over (developed or
undeveloped) City right-of-way. Encroaching Rockeries shall be immediately removed
by order of the Public Works Director.
• Rockeries shall not be constructed over public utility easements, or be constructed to
adversely affect drainage, or create a sight distance hazard.
• Rockeries that support a surcharge shall not be permitted. (See Engineering Standard
Detail E8.12.1, attached.)
• Rockeries that impound flammable liquids shall not be permitted.
• Rockeries exceeding three feet in Setback Area Height are not permitted. (See Setback
Area Height Definition above.)
• Rockeries exceeding three (3) feet in height shall not be placed against fill.
EXEMPTIONS FROM PERMIT REQUIREMENTS
A Rockery permit is not required for the following conditions:
• Rockeries less than eight (8) feet in height provided the following conditions apply: the
Rockery is designed for erosion protection purposes only, the Rockery is placed against an
existing cut slope, and none of the other conditions below (numbers 1-4 under General permit
requirements) apply. (See Rockery Height Definition above.)
• For Rockeries proposed for construction in conjunction with an approved subdivision or
short plat, a separate Rockery permit is not required. However, Rockery details shall be
included on the subdivision/short plat civil drawings based on the submittal requirements of
this handout. Civil plan approval (stamped and signed by the City Engineer) will constitute
Rockery approval.
• Rockeries less than eight (8) feet in height proposed on an individual lot with a Critical
Areas determination of Erosion Hazard Area only. Other Critical Areas determinations do
not apply to this exemption.
• Rockeries that retain filled slopes to a maximum height of three (3) feet. (See Setback
Area Height Definition above.)
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GENERAL PERMIT_ REQUIREMENTS (See .gage S for submittal requirements)
A Rockery permit shall be required when any of the following conditions apply:
1. Rockeries eight (8) feet in height orreg ater Lee Rockery Height definition above)
• Plans must be designed and stamped by a WA State licensed Engineer
• Design calculations shall be submitted with the plans, stamped by the Engineer of
record
• Rockeries are limited to a maximum height of twelve (12) feet for cut slopes
• Special inspection required
2. Rockeries of any height located in a designated Critical Area other than Erosion Hazard
Area
• Plans must be designed and stamped by a WA State licensed Engineer and comply with
ECDC Chapter 23.80
• Design calculations shall be submitted with the pians (required to be submitted only
when peer review is required), stamped by the Engineer of record
• Peer review and special inspection are required for all Rockeries located in designated
Geologically Hazardous Critical Areas
• Peer review and special inspection required for Rockeries greater than 8 feet in height
in any other designated Critical Area
3. Rockeries of gny height located within the ma ped. Earth Subsidence Landslide Hazard
Area of North Edmonds ESLHA ma on file at Ciy Hall
• Plans must be designed and stamped by a WA State licensed Engineer and comply with
ECDC Chapters 19.10 & 23.80
• Design calculations shall be submitted with the plans, stamped by the Engineer of
record
• Peer review and special inspections required
4. Terraced Rockeries are subject to the noted conditions above and the following conditions
apply:
• Each tier is considered to be a separate Rockery (if any individual tier exceeds the
threshold for a permit then a permit is required for the entire terraced structure)
• The upper tier shall be setback from the lower tier a distance equal to or greater than the
height of the lower Rockery tier. (See Engineering Standard Details E8.9 and E8.10,
attached.)
• If the distance between the upper tier and the lower tier is less than the height of the
lower tier then the lower tier shall be considered to support a surcharge from the upper
tier, which is not permitted.
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GENERAL REQUIREMENTS
If any of the requirements- below cannot be met, an engineered earth retaining wall structure shall
be required. (See Handout #B62. The City Engineer may require an engineered earth retaining
wall structure for proposals located adjacent to the City right-of-way.
1. The maximum allowable height above finished grade measured from the toe of the Rockery
shall be twelve (12) feet.
2. The cut slope behind the Rockery shall be free standing and the soil behind the Rockery
shall be firm, stable, undisturbed, and competent native soil.
3. The slope behind the top of Rockery shall not be steeper than 2:1 (Horizontal:Vertical).
(See Engineering Standard Detail E8.9, attached.)
4. The slope (batter) of the Rockery shall not be steeper than. 1:6 (Horizontal: Vertical). (See
Engineering Standard Detail E8.9, attached.)
5. Rockeries on private property adjacent to City right-of-way shall be setback from the City
right-of-way a minimum horizontal distance equal to the height of the Rockery_
6. A two (2) foot minimum shy distance shall be maintained from Rockeries to the edge of
roads (including private access roads serving 3 or more lots), streets and alleys.
7. Roads, driveways, buildings, or any other conditions imposing a surcharge load shall not be
located within a horizontal distance equal to the height of the Rockery.
S. Temporary Spoil. Unless substantiated by the applicant's Geotechnical Engineer, temporary
spoil or stockpiling shall be placed no closer than two (2) feet from the surface edge of the
excavation, measured from the nearest base of the spoil to the cut. Spoil should be placed so
that it channels rainwater and other run-off water away from the excavation. Permanent
spoils are considered to be fill and are subject to IBC permitting and fill requirements. (A
separate fill/grading permit may be required.)
GENERAL INSPECTION REQUIREMENTS
1. If the Rockery is located on private property and is permitted as part of a building permit or is
a separate Rockery permit, the property owner is responsible to call the City Building
Inspection line (425-771-0220 ext. 1333) for the following inspections, including but not
limited to: Location and setbacks, keyway, under drain, rock size and placement and final
inspection.
2. If the Rockery is constructed as part of a subdivision/short plat site improvement, the
property owner is responsible to call the City Engineering Inspection line (425-771-0220 ext.
1326) for the noted inspections above.
SPECIAL INSPECTION REQUIREMENTS
• The Geotechnical Engineer of record shall verify conformance with the project specific
Rockery design including but not limited to: soil bearing conditions, contractor compaction
methods, rock placement procedures, rock material and sizes, rock filter layer and gravel
backfill for drainage, etc.
• The Geotechnical Engineer of Record shall also monitor the project and provide corrective
action recommendations as needed.
• Field reports by the Geotechnical Engineer of Record shall be submitted to the Building
Division for review and approval for private lot development. For subdivision and short plat
work field reports shall be submitted to the Engineering Division for review and approval.
L UEMPIBUILDINCIHANDOUT [CODES 20031ROCKERY B63.DOC Page 4 of 9
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PERMIT SUBMITTAL RE UIREMENTS
1. CRITICAL AREAS CHECKLIST (See Handout 9P20)
A Critical Areas Determination, issued by the Planning Division, must be completed and on file
with the City. Provide applicable information as indicated by the decision for compliance with
ECDC Chapter 23.80. Lots located in the mapped Earth Subsidence and Landslide Hazard Area
(ESLHA) of North Edmonds are subject to City Ordinance #2661 and ECDC Chapter 19.10 and
ECDC Chapter 23.80.
2. SOILS INVESTIGATION OR SOILS REPORT
The classification of soil and design bearing capacity must be determined based on observation
and tests of the soil materials disclosed by borings or excavations. Such work shall be performed
by a Washington State licensed Professional Geotechnical Engineer or Engineering Geologist.
Soils investigationlreport recommendations shall be incorporated into the Rockery design and
shall conform to the requirements of IBC 1802 and IBC Table 1804.2.
3. GRADING PLAN Three (3) copies, scaled 1"=20'. (See Handout #B37)
When fill or grading for Rockeries exceeds 50 cubic yards, a separate grading plan with yardage
calculations must be submitted (additional permit fees required). Exception: Grading in
designated Critical Areas or within the mapped ESLHA requires grading plans, peer review and
additional permit fees regardless of the amount of grading or fill.
Grading plans must show: existing grade contours and proposed finished grades at two (2) foot
intervals for lots with slopes of up to 15%. For lots with 15% slopes or greater, show all grades
at five (5) foot intervals. Clearly define grading limits and trees to be removed and/or retained.
Detail permanent slope protection, indicate setbacks from top and toe of slopes, the slope of the
lot and methods for temporary and permanent erosion control. Provide calculations and specify
the number of cubic yards to be removed, filled, or graded. NOTE: When grading exceeds 499
cubic yards, an Environmental Checklist and APO list must be submitted for SEPA review, (a
separate fee is required for SEPA review).
4. PLOT PLAN Three (3) copies, scaled 1'-20', one of the three plot plans must be
no larger than 81/2" x 14" with the following: (See Handout #B57)
a) North arrow, property line dimensions, streets, alleys, driveways, parking areas, etc.
b) Clearly show edge of City right-of-way, curb, gutter, sidewalk, street trees, etc.
c) Detail public and private access and utility easements that encumber the property
*Provide copies of all recorded easements that affect the property
d) Show location of existing house, garage, decks, etc. within the property
e) Show location of streams, creeks, drainage courses, etc. within the property
f) Clearly show the proposed location of the Rockery and distance to property lines
g) Clearly show how Rockery drain pipe will connect or discharge to an approved drainage
system
h) Indicate top and bottom elevations at 5 foot intervals to clearly show height of the
Rockery along its entire length
i) Show existing and proposed grade contours at two (2) foot linear intervals for slopes up
to 15% and five (5) foot linear intervals for slopes exceeding 15% slope
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S. SECTION AND ELEVATION VIEWS Two (2) copies, stamped and signed by a
Washington State licensed Engineer, with the following:
a) Provide a typical section view of the Rockery. (See Engineering Standard Detail ES_ 9,
attached.)
b) Show and call out size of proposed rock. (See Table 1 on Page 7 of this handout.)
c) Drainage provisions behind Rockery (piping size and material) and backfill proposed.
Show clearly how Rockery drain pipe will connect or discharge to an approved drainage
system. (See Engineering Standard Detail E8.9, attached.)
6. ROCKERY DESIGN CALCULATIONS Two (2) copies, required to be
submitted only when peer review is required stamped and signed by a WA State licensed
Engineer and shall include: soils classification, unit weight of soil, allowable bearing pressure,
active and passive earth pressures, liquefaction potential, coefficient of friction, seismic loads,
site specific surcharge loads, water table information, grading calculations and the maximum
inclination of the cut slope at the toe and backside of the rockery. The Engineer shall also
specify rock specifications for the specific project.
7. EROSION AND SEDIMENTATION CONTROL PLAN (See Handout E472)
Submit three (3) copies of Erosion and Sedimentation Control Plans per ECDC Chapter 18.30.
(See Engineering Standard Details E1.1, E1.1. l and E1.3, attached.)
8. LETTER FROM GEOTECHNICAL ENGINEER SPECIFICALLY ADDRESSING
THE CRITERIA OF ECDC CHAPTER 23.80.070
For Rockeries in designated geologically hazardous Critical Areas or in the mapped ESLHA, the
Geotechnical Engineer of record shall submit a stamped and signed letter acknowledging that the
criteria of ECDC Chapter 23.80.070 has been reviewed and all applicable design considerations
for code compliance have been incorporated into the plans.
NOTE: THE PURPOSE OF THIS HANDOUT IS TO ASSIST THE PUBLIC IN COMPLYING WITH
DETAILED PERMIT SUBMITTAL REQUIREMENTS. IT IS NOT A COMPLETE LIST OF PERMIT OR
CODE REQUIREMENTS AND SHOULD NOT BE USED AS A SUBSTITUTE FOR APPLICABLE LAWS AND
REGULATIONS. IT IS THE RESPONSIBILITY OF THE OWNER/DESIGN PROFESSIONAL TO REVIEW
THE SUBMITTAL FOR COMPLETENESS AND APPLICABILITY TO OTHER CODES. ONLY COMPLETE
APPLICATIONS WILL BE ACCEPTED BY THE CITY FOR REVIEW
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DESIGN CRITERIA FOR ROCKERIES
General
When a permit is required, the submitted plans, specifications, engineering calculations,
diagrams, soil investigation report, and other data shall conform to International Building Code
provisions. Design calculations require knowledge of the active soils behind the rockery, slope
stability, surcharge loads, equivalent fluid pressure and physical properties of the soils. A soils
report must be submitted by a State licensed Geotechnical Engineer for review with the rockery
submittal.
Backfilling is critical. The purpose of the fill material is to hold the natural soils in place without
allowing the soils to shift or to erode the rockery voids. The rockery plans shall indicate the
number of cubic yards of fill material that will be used on the project. When fill is placed behind
a rockery, the soil parameters for design are based on the knowledge of the proposed fill soils and
the anticipated control of the compaction. Special inspection by a licensed Geotechnical
Engineer may be required to verify that the soils and compaction procedures are proper and the
compacted soils properties achieve the design parameters.
Rockeries should be designed based on engineering methods to prevent sliding or overturning
between rocks or at the base. The required weight should be calculated above each one foot
intersection to determine the friction necessary to resist sliding, or the moment to resist
overturning. Rock design parameters should include the weight of the rock, the resistance to
sliding between rocks, and the percentage of voids. Allowable voids will vary depending on the
shape of the rocks; a maximum of 20% voids is allowed.
Rock Material
All rock shall be clean, sound, angular ledge rock that is resistant to weathering. The rock
material shall be as nearly rectangular as possible with the longest dimension of any individual
rock not exceeding three times its shortest length. No stone shall be used which does not extend
through the entire width of the rockery. The rock shall be hard, sound, durable, and free of
cracks, weathered portions, seams, and other defects. The Engineer of record must call out rock
specifications for the project.
Rock Sizes
For rock sizes relative to the rockery height, refer to Table 1 below as shown on the attached
diagrams. The rockery plans shall include the rock sizes to be used in the specific proposal.
Approximate rock sizes are as follows:
Table 1
Rock Size Requirements
Size
Approximate Weight
(Pounds)
Approximate Diameter
Inches
2 -Man
200-700
18-28
3 -Man
700-2000
28-36
4 -Man
2000-4000
3648
5 -Man
4000-6000
48-54
6 -Man
6000-8000
54-60
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Rack Filter Layer
The rock filter layer shall consist of clean quarry spalls with a maximum size of four inches (4")
and a minimum size of three quarters inches (314"). This material shall be placed with a twelve
inch (12") minimum width between the entire facing and the cut slope. The rock filter material
shall be placed in lifts with an elevation approximately six inches (6") below the top of each
course of rocks as they are placed, until the uppermost course is placed. Any rock filter material
on the bearing surface of one rock course shall be removed before setting the next course.
Quarry rock that is to be used as the rock filter layer shall meet the requirements defined below in
Table 2:
Table 2
U.S. Standard
Sieve Size
Percent Passing
By Weight
4°
100
2"
40 Maximum
314"
10 Maximum
Gravel Backfill for Drains
A system shall be designed to intercept ground water behind the rockery in order to prevent the
erosion of soil. The intercepted groundwater shall be channeled to an approved drainage system,
specify all drainage materials (piping, type of backfill, etc.) on the drainage plan; note the backfill
that surrounds the drainage pipe shall conform to WSDOTIAPWA 9-03.12(4) outlined below in
Table 3:
Table 3
Sieve Size
Percent Passing
1" Square
100
---
3/a" Square
80
100
318" S uare
10
40
US No. 4
0
4
US No. 200
i 0
2
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CONSTRUCTION CRITERIA FOR ROCKERIES
Keyway
A keyway consisting of a shallow trench shall be constructed the entire length of the rockery.
The minimum keyway depth shall be the larger of twelve inches (12") or half the diameter of the
largest rock (whichever is larger) to be used in the bottom course of the wall. The keyway shall
also be slightly declined toward the face that is to be protected and shall be excavated for the full
rockery width, including the rock filter layer. The keyway subgrade shall be firm and is subject
to inspection and approval by the Engineer of record when required by the City.
Underdrain
A minimum six inch (6") diameter perforated or slotted drainpipe shall be placed in a shallow
excavated trench located along the inside edge of the keyway. The pipe shall be placed on and
surrounded by approved backfill material to a minimum height of eighteen inches (18") above
the bottom of the pipe. A filter fabric shall surround the gravel backfill and shall have a
minimum of twelve inch (12") overlap along the top surface of the gravel. The Engineer of
record may waive this requirement for fabric (if shown and included within the soils report) that
soils and water conditions make it unnecessary. The perforated drainpipe shall be connected to
the storm drainage system (other than detention) or an approved outfall.
Rock Selection and Placement
The base course of rocks shall be bedded on firm, undisturbed earth (or prepared keyway as
required) and shall be in full contact with the soil. Additional shaping of the earth surface may
be required to achieve full soil contact. All rockeries shall be constructed in a manner such that
no continuous joint planes are present in either the vertical or horizontal direction. Rocks shall
be placed such that the longitudinal axis of the rock is at right angles to the face. Each rock shall
be supported by at least two rocks in the course below_ Whenever possible, rocks should be
placed to achieve bearing between flat rock surfaces. Rock selection and placement shall
minimize voids. Voids in the exposed face shall not exceed six inches (6") across in any
direction. After the setting of each course, the voids shall be "chinked" on the backside of the
wall using quarry rock to eliminate any voids sufficient to pass a two inch (2") square probe.
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