4711 GLENHAVEN DR 2016-01-01 MF Import

Mr. Richard Sullivan July 25, 1984 � Page 2 On Mukilteo Boulevard �_ che intersection with Ridgemont Drive north of the subject property is a sand pit. Exposed in this pit is a tan, dense to fine to medium sand. No indications of springs or groundwater Nere observed on the subject property or in the exposures. No water Mas flowing in the ravine bottom at the times � of my visit 6ut may flow intermittently during the rainy season. The slope of most of the property, Nith the exception of the extreme easterr edge, is 1 vertical on 2 horizontal (1V on 2H) . Considering the soils observed in the exposures, it is my opinion that these slopes may be locally oversteepened by excavation to provide driveways and residence foundations. Finished excavated slopes of not steeper than 1V on 1.5H are reasonable. Slopes steeper than this will require support by a retaining structure. Fills may be planned on the 1V on 2H hillside provided topsoil and loose uppe r soils, probably to an average depth of 2 feet, are stripped and filt placed in horizontal layers, compacted, and bonded to the hills�de. Bonding is achieved by cutting into the hillside with a dozer blade as each layer is placed, thus providing a series of alternating benches and vertical cuts beneath the fill . All grading and site preparation work must be performed during the dry summer months. Fill material probably will require wetting or drying to achieve satisfactory compaction. Al1 compacted fills should be observed and tested by a geotechnical engineer or his representative. Cut slopes as steep as 1V on 1.5H may be used. These slopes must be protected against erosion. 5lopes steeper than 1V on 1.5H will require a retaining structure. Residences mav be sited on the ridges or on the slopes. Foundations on 1V on 2H slopes may consist of stepped footing walls generally oriented normal and parallel to the contour. Footings buried a minimum of 2 feet probably will be needed to reach through surficial loose soils. Below ground living space hould be protected from water seepage by a footing drain, clean sand and g;avel wall backfill to within 18 inches of ground surface, and a water repellent treatment on the outside of the wall . _ Residences may be elevated above the ground surface, such as a pole house or a house on piers. Piers or poles should be reinforced and imbedded below the ground surface a depth sufficient to resist downslope soil creep, probably a minimum of six feet.