1024 35TH ST 2016-01-01 MF Import

Mascio Residence —1024 3a'" Street Everett, WA July 7, 2006 The stru�Kure is a one-story, building with an attached, converted garage. The original, portion of residence consists of a wood-framed building with a crawl space. The attached, converted garage area appears to be slab-on-arade construction with perimeter continuous footings. The area where the settlement has occ�rred is the southwest corner of the original house. The original house was built in 1960. The foundation walls appear to consist of approximately 6-inch thick reinforced concrete with a footiny. There do not appear to be any mechanical connections between the fowidation wall and the framed portions of the house. SITE CHARACTERIZATION AND SUBSURFACE CONDITIONS We reviewed the "Geologic Map of Washington" (2002) compiled b�i Schuster, Eric J. The soils near the project site are mapped as "Quaternary sediments" (Qa). 'Quaternary sediments" (Qg) are dominantly glacial drift; includes alluvium. We completed a shallow excavation at the southwest side of the residence using manuai aquipment to evaluate the subsurface soii and groundwater conditions to a depth of about 9.5 feet belo�v the adjacent site grade. The soila encountered from gradn to 4.5 feet below existing grade consist of dark brown, moist, silty, medium to coarse SAND. The soils encountered from 4.5 feet to the termination of the hole at 9.5 feet generally consist of wet, silty SAND/sandy SILTS with organics, charcoal, giass, and wire (fill). We encountered ground water at 7.0 feet. We estimated that the bottom of foundation wall depth is about 22 inches below the adjacent site grade. CONCLUSIONS AND RECOMMEMDATIONS it is our opinion that the settlement, which has occurred along the south and west side of the residence, is most lilcely a result of concentrated, foundation wall loads bearing on loose, comxessible fill soils. The concentra'ted loads at the base of the foundation walls exceeded the bearing capacity of the underlyin�, loose soils ard resulted in a bearing capacity failure. The result of the bearing capacity failure was settlEment. Any new, add:tional loads on soft, compressible soils can result in additional se;tlement. Saturation of loose, silty soils can reduce the shear strength of the soil and can lead to settlement. A significant increase in soil moisture content can result frorr seasonal gro�ndwater level fluctuations or poor drainage conditions. We have discussed the p,oposed foundation stabilization with the contractor, and it is our opinion that the perimeter foundatiuns of the residence at poRions of the south and west foundation walls of the residence can be re-leveled and stabilized to reduce the ri�k of future settlement as proposed. Otto Rosenau & Associates, Inc. Page 2 of 4