4320 THOMSON AVE 2023-08-10 - Laserfiche WebLink

Drew Martin From: Drew Martin Sent: Wednesday, January 5, 2022 3:41 PM To: Stefano Zucca Cc: Michael Stevens; chevy@cgengineering.com; John Bertrand; Joe Galusha Subject: RE: [EXTERNAL] RE: 4320 Thomson Drive., permit B2104-040 and D2104-004 - Planning Corrections Hello, Stefano. I was able to talk with Chevy at CG, and it appears some revision to both the civil and architectural drawings may be required. I'm not sure if the structural drawings will also need revision. I had previously reviewed and approved the building permit. However, based on the geotechnical report and recent discussion, I'm issuing the comments below. This email will serve as the review letter. The comments may apply to multiple disciplines, so all disciplines should review and address as needed. I recommend discussing these as a design team and contacting me if needed. Two hard copies of revised documents, including calculations and geotechnical information if required, should be submitted for review. Comments 1. Sheets C3.1 and C3.3 include a rockery to retain the steep slope to the west of the building. The design is based on the City of Everett standard per Detail 3/C3.3. The design team should verify the standard design is appropriate to the project. Note that the plan on Sheet C3.1 does not show the drainage system at the base of the wall. Continuing with the previous comment, the geotechnical report by GeoTest Services, Inc., dated 04/12/2019, appears to state on Page 9 under "Mitigation of Geologic Hazards" that the slope is prone to future erosion. Furthermore, the foundation wall for the building should be designed as a retaining wall with a maximum possible retained height of 5 feet. It is noted that the assumptions that this is based on are not clear, and that the design concept for the building may have changed after the report was produced. It appears that the rockery may have been intended to mitigate the impacts of erosion on the west side of the building. However, the City of Everett detail does not include additional erosion measures to retain soil from flowing over the top of the wall, nor is the wall designed for addition surcharge pressures due to increase depth build-up behind the wall. The design team should clarify how the erosion issue identified in the geotechnical report has been addressed in the proposed project. The location of the rockery behind the house does not appear to be specified in the plans on Sheets C3.1 and A1.11. Note that it is understood that an updated C3.1 may have been submitted for the PW permit versus the copy included in the building permit submittal. The rockery is depicted within 3 feet of the building. The sections on Sheet A3.11 depict the wall as close as 2 feet from the building. The west wall includes emergency egress windows for two bedrooms. Due to the height of the retained soil behind the wall being higher than the window will, this creates a below -grade condition for the windows. A minimum 3 foot clearance should be provided between the window surfaces and the rockery. Other revisions based on the requirements of IRC Section R310.2 may apply. 4. Detail 2/C3.1 shows the grade at the building perimeter sloping away from the building as required for drainage per IRC Section R401.3. However, the architectural building sections on Sheet A3.10 appear to show the soil sloping towards the building; note that the soil against the garage exterior wall in Section 1 appears to be 1113