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TO: Michael Sippo
City of Renton Development Engineering
DATE: October 27, 2025
FROM: James Daley
Tacoma - (253) 383-2422
PERMIT NO.: C24002558
PERMIT NAME: Talbot Hill Elementary School Site
Improvements
SUBJECT: Talbot Hill elementary School TIR Addendum
This project memo is an addendum to the approved Talbot Hill Elementary School Site Improvements Technical
Information Report under Permit No. C24002558. This addendum proposes the maintenance of an asphalt paved
pedestrian walkway connecting the school to the adjacent neighborhood south of the school. The existing asphalt
paved walkway is approximately 140-ft long and varies from 6-ft wide with a total impervious area cover of
approximately 840 square feet. This addendum proposes to demolish the existing asphalt paved pedestrian
walkway and replace it in kind. The new asphalt paved pedestrian walkway will maintain the same dimensions
and cover as the existing walkway. The work related to this addendum does not propose to increase the existing
impervious cover. The walkway drains to an existing type 30 catch basin located on the Talbot Hill Elementary
School property at the north end of the path. Please refer to the attached record drawing for the location of the
walkway to be replaced and the catch basin it drains to, in-plan CB #12. The replacement of the asphalt paved
walkway will maintain the existing drainage conditions. Stormwater runoff generated by the walkway will
sheetflow to, and be collected by, the existing catch basin CB #12. From the existing catch basin stormwater will
be conveyed via the existing stormwater system of pipes to the existing stormwater treatment and detention pond.
Addendum to Conditions and Requirements:
CR 3: Flow Control – Flow control is provided by the existing engineered stormwater treatment and detention
pond. The new pedestrian walkway will not increase the total site impervious cover and therefore will not
increase flows to the pond.
CR 4: Conveyance System – The existing stormwater system will not increase flows and therefore the
conveyance capacity will not change.
CR 8: Water Quality – The new pedestrian path is non-pollution generating and therefore will not change the level
of treatment required. Treatment is provided by the existing engineered treatment and detention pond.
JAD/
c: David Nason - AHBL
Andrew Hollenback – Renton School District
Q:\2023\2230870\10_CIV\NON_CAD\REPORTS\Storm - Site\TIR Addendum - for existing path\20251027_TIR Addendum_Talbot Hill ES.docx
10/28/2025
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TEL www.ahbl.comWEBTELwww.ahbl.comWEBTELwww.ahbl.comWEB
2215 North 30th Street, Suite 300 Tacoma, WA 98403
253.383.2422TEL www.ahbl.comWEB
TACOMA SEATTLE SPOKANE TRI-CITIES
Know what's below.
before you dig.Call
R
253.383.2572 FAX
TALBOT HILL
ELEMENTARY SCHOOL
2230870.10
FIELD ADDENDUM
OCTOBER 27, 2025
JAD JAD DCN
1
TALBOT HILL ELEMENTARY SCHOOL
A PORTION OF THE NE 1/4 OF THE NE 1/4 OF SEC. 30, TWN. 23 N.,
RGE. 05 E. W.M. CITY OF RENTON, KING COUNTY, WASHINGTON.
RENTON
SCHOOL DISTRICT
ANDREW HOLLENBACK
300 SOUTHWEST 7TH STREET
RENTON, WA 98057
10/27/2025 SITE ADDENDUM FOR PATH
C2
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0
2
5
5
8
PERMIT REVISIONS
C3.0
1
FIELD ADDENDUM
1
C3.0
SUBGRADE
HMA CL 1/2", PG 58S-22 PER
WSDOT 9-03.8(6) AND 9-02.1(4)
2-1/2"
CRUSHED SURFACING BASE
COURSE PER WSDOT 9-03.9(3)
4"
NOTES:
1.DEPTHS INDICATED ARE COMPACTED THICKNESS.
2.HMA SHALL BE COMPACTED TO A TARGET AVERAGE DENSITY OF 92% BASED ON THE RICE THEORETICAL MAXIMUM
DENSITY PER ASTM D-2041. INDIVIDUAL LOCATIONS SHALL BE COMPACTED NOT LESS THAN 90% NOR MORE THAN 96%.
3.ALL ASPHALT BASE MATERIAL SHALL BE COMPACTED TO A MINIMUM DENSITY OF 95% BASED ON THE MODIFIED
PROCTOR MAXIMUM DRY DENSITY PER ASTM D-1557.
4.SUBGRADE SHALL BE COMPACTED TO A FIRM AND UNYIELDING CONDITION PRIOR TO PLACEMENT OF ANY PAVEMENT
LAYERS. ANY LOCALIZED ZONES OF SOFT, ORGANIC-RICH, OR DEBRIS-LADEN SOILS SHOULD BE OVEREXCAVATED
AND REPLACED WITH STRUCTURAL FILL MATERIAL.
5.SEAL JOINTS WITH EMULSIFIED ASPHALT PER PROJECT SPECIFICATIONS.
1 NOT TO SCALE
ASPHALT PAVEMENT - STANDARD DUTY
LEGEND
ASPHALT PAVEMENT - STANDARD DUTY
REMOVE AND REPLACE ASPHALT
PEDESTRIAN WALKWAY
1
C3.0
Stormwater generated by
the new walkway drains to
this catch basin, CB #12
Existing asphalt paved
pedestrian walkway to
be replaced
Walkway connection
to Talbot Hill ES