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6 <br /> ♦ <br /> McCann Property Geotechnical Services Report <br /> 2610 Viewcrest Avenue,Everett, Washington <br /> Following compaction and approval of the slab bearing soils, a capillary break layer consisting of <br /> a minimum of 4 inches of washed pea gravel, washed crushed rock or clean, coarse grained, <br /> granular soils and a heavy duty (minimum 10 mil), polyethylene plastic vapor barrier should be <br /> provided under any floor slabs where moisture intrusion is a concern. If the vapor barrier becomes <br /> compromised in any way during construction it should be replaced or an additional layer added. <br /> Penetrations through the vapor barrier should be wrapped and taped. All seams should be <br /> overlapped a minimum of 2 feet. <br /> Retaining Walls <br /> Based on the current site plan no retaining walls are planned for the project. Small rockeries are <br /> planned along the east and west sides of the driveway. The rockeries should be built according to <br /> ARC (Association of Rockery Contractors)standards,especially where the rockery exceeds 3 feet <br /> in height. <br /> Drainage <br /> Storm water from impermeable surfaces should be collected and discharged into a city approved <br /> storm water drainage system. Footing drains should be installed around the exterior footings with <br /> discharge to a catch basin and ultimately into the storm drain system. The footing drains should <br /> consist of 4-inch diameter,perforated pvc pipe,bedded in washed drain rock and covered entirely <br /> with washed drain rock that is wrapped in geotextile filter cloth. The drains should be placed at <br /> the bottom of the footings and sloped to gravity drain to the catch basin. Appropriate cleanouts <br /> should be installed to allow for periodic maintenance of the drain pipes. <br /> Foundation walls taller than 3 feet should be provided a wall drain to reduce the potential for <br /> hydrostatic pressure buildup against the wall. The wall drain should consist of either a minimum <br /> of 12 inches of washed drain rock, wall backfill containing less than 3% fines or a geotextile <br /> drainage mat such as MiraDrain or DeltaDrain. The wall drains must hydraulically connect to the <br /> footing drain system. All drainage material should extend to within 18 inches of ground surface <br /> before being capped in order to prevent surface water from entering the wall drain. <br /> We understand that infiltration of storm water will be the primary methodology for storm water <br /> disposal on the site. Design of a suitable drainage system will require a project civil engineer <br /> unless acceptable prescriptive designs, which are very conservative, are utilized. If needed, we <br /> will work with the project civil engineer to provide required soils information for the site. <br /> Erosion Control <br /> Suitable best management practice (BMP) erosion control measures should be implemented for <br /> the project. The presence of gentle slopes and granular soils on the site will aid in reducing the <br /> amount of potential sediment laden runoff from the parcel. A silt fence should be installed as per <br /> city requirements along the lower portions of the site. Soil stockpiles should be covered with <br /> Gary A.Flowers,PLLC. <br /> 5205 23'd Avenue W Everett,Washington 98203 206-819-4304 <br /> 4 <br />