2109 MCDOUGALL AVE 2018-01-02 MF Import

I Geotechnical Engineering Eva,,mlion 2109 McDougall Ave, Everett -Cobb February 14, 2007 RMI File No. 34206 Page 2 Geologic Conditions Landforms within this region comprise a system of glacially sculptured features, %ehich have been exposed by post -glacial erosion. Locally, the terrain of this area has been glacially modified. The soils were placed either prior to, u r during the latest glaciation of the Puget Lowland area. Glacial ice last occupied the region during the late Pleistocene epoch, some 10,000 to 13,000 years before the present. The latest glacial advance over the area is referred to as the Vashon Starle of the Fraser Glaciation, which deposited the glacial materials on site. Literature Review The Geologic Map of Surflcial Deposits in the Seattle 30-by 60- minute Quadrangle by Yount ct al notes that the area contains glacial deposits of the Vashon till, Qvt. Site Conditions You had dug a test pit on March 26, 2006 about 4 feet deep at about 5 feet from the footing of the home on the socth side where you plan to construct the addition. We logged it as having 6 inches of topsoil over 18 inches of weathered reddish -brown dense sand. Beneath this layer was a very dense grey sand which we interpreted to be the Vashon till. Hydrologic Conditions No water was observed in the test pit. CONCLUSIONS AND RECOMMENDATIONS General It is our opinion that the site is compatible. from n geotechnical engineering standpoint, with the proposed development. The underlying deposits on the lot on which the house addition wiit be built typically have high strength and are considered stable. It is good practice to use exterior looting drains around all of the structures v h=re moisture control is important. Footing drains should be installed at least 1 foot below any finished Boor slab. The drains should consist of4-inch-diameter, rigid, perforated PVC pipe that is surrounded by free -draining material, such as pea gravel and wrapped in a non -woven flier fabric. Footing drains should discharge into RMI ASSOCIATES LLC 0