4901 FOWLER AVE 2018-01-02 MF Import

Based on our site visit and review of the Geologic Map of the Everett Quadrangle by James Minard, 1981, we interpret that the site is underlain by Vashon advance outwash (Qva). Vashon advance outwash typically consists of sand with pebbles and gravel that has been consolidated by approximately 3000 feet of glacial ice. The soil that composes the outer face (typically the outer I to 3 feet) of a slope most often consist of colluvium. Colluvium is gravity transported material that has weathered from its original depositional position to create the existing slope. Based on the assumed subsurface conditions described above, the slope should be considered stable in its present condition and at its present angle. Based on our visual review of the site, the site geology and our understanding of the proposed construction, it is our opinion that the property is compatible, from a geotechnical perspective, with the proposed residentiai construction. Furthermore, once the proposed home is completed the stability of the slope should not be reduced because the slopes will either remain in their present stable, vegetated condition, be retained by retaining (basement) walls or sloped to a less steep angle. In our opinion, temporary construction slopes should be the responsibility of the contractor and should be determined during construction based on the encountered conditions. For estimating purposes, however, we suggest that temporary, unsupported cut slopes be planned at a maximuri slope of 1H:1V (Horizontal: Vertical) for slopes less than 5 feet high and 1.5H:1V for slopes greater than 5 feet high and up to 10 feet high. Any cuts proposed over 10 feet high should be reviewed by our office prior to their completion. Even at these inclinations, some sloughing and raveling may occur and cut slopes may have to be adjusted in the field. Permanent slopes that are disturbed during construction should be constructed to a maximum 2H:1V ine!ination. This includes backfill around the home or cuts in the crawlspace. Natural undisturbed slopes not impacted during construction snould be left in their present vegetated condition. Soils exposed during construction should be revegetated as soon as possible after construction to reduce erosion. Foundations may be placed to bear on the natural medium dense or dense sands for suitable foundation support for typical residential foundation loads. It should be noted that the area bounded by lines extending downward at 1H:1 V (Horizontal: Vertical) from any footing must not intersect another footing or intersect a filled area which has not been compacted to 95 percent of ASTM-D1557. In addition, a 1.5H:1V line extending down from any footing must not daylight because sloughing or raveling of the adjacent soils maj eventually undermine the footing. Thus, footings should not be placed near the edge of steps or cuts in the foundation bearing soils. It is recommended that footing subgrades by inspected by a representative of AESI to verify that conditions are as anticipated.