5117 27TH AVE W 2025-05-29 - Laserfiche WebLink

• saUED � JUL 15 2022 COBALT Cobalt Geosciences,LLC GEOSCIENCES P.O.Box 82243 I�, �. �J�j'RE '�'r Kenmore,Washington 98028 Permit Services December 20,2021 RR Foundation Specialist Attn:Barbara Stasiak and/or Amber Miller RE: Limited Geotechnical Evaluation Foundation Mitigation 5117�7th Avenue West Everett,Washington In accordance with your authorization, Cobalt Geosciences, LLC has prepared this letter to discuss the results of our limited geotechnical evaluation at the above-referenced location. Site and Project Description The site is located at 5117 �7th Avenue West in Everett, Washington. The site consists of one rectangular shaped parcel(No.00567900200902)with a total area of about 0.22 acres. The central portion of the site is developed with a residence and driveway. The remainder of the property is vegetated with grasses, bushes, and sparse trees. The site slopes downward from south to north at magnitudes of 5 to 20 percent and relief of about 9 feet. The site is bordered to the north, south, and east by residences, and to the west by 27th Avenue West. We understand that portions of the residence have settled about 2.5 inches over time, likely beginning after construction and potentially continuing today. The most significant settlement is in the northern margin of the house. The project includes installation of at least 11 helical anchors and 3 driven piers. Anchors will be P attached with steel brackets and angle iron if necessary. Anchors are anticipated to be driven to refusal below foundation elements. Lifting may be performed as allowed by the structure. Additional composite pads will be used for crawlspace column areas. Area Geology The site lies within the Puget Lowland. The lowland is part of a regional north-south trending trough that extends from southwestern British Columbia to near Eugene, Oregon. North of Olympia, Washington, this lowland is glacially carved,with a depositional and erosional history including at least four separate glacial advances/retreats. The Puget Lowland is bounded to the west by the Olympic Mountains and to the east by the Cascade Range. The lowland is filled with glacial and non-glacial sediments consisting of interbedded gravel,sand,silt,till,and peat lenses. The Geologic Map of the Everett Quadrangle, indicates that the site is underlain by Vashon Glacial Till. The till consists of a nonsorted mixture of silt, sand, clay, gravel, and cobbles. These deposits typically become dense within the upper 15 feet,below a weathered zone. www.cobaltgeo.com (206)331-1097 lB