7424 BEVERLY LN 2021-12-13 - Laserfiche WebLink

Ms. Nell Lund Site Inspection 7424 Beverly Ln Everett, WA GEOLOGICAL SETTING AND SOILS March 2, 2021 PageJ,211" The geologic setting in this area is comprised of deposits of Vashon till which consists of mud, sand, pebbles, cobbles, and boulders (Upper Pleistocene) (USGS National Geologic Map Database). According to the Washington Geologic Information Portal, the site has not been analyzed for a landslide hazard but is gently sloped. It is our opinion that the settlement is a result of improper foundation drainage, poor soil conditions, and/or undersized foundations. We believe that a suitable support can be achieved by installing helical piles. Based on the site conditions, a full geotechnical report is not necessary. Preliminary soil data was obtained from the Web Soil Survey from Natural Resources Conservation Service produced by the United States Department of Agriculture. This soils survey indicates that the primary soil at the residence is classified as Alderwood-Urban land complex. This soil has a moderate infiltration rate and a moderate rate of water transmission. Alderwood- Urban land complex has a low shrink -swell potential with Plasticity Index ranging from NP-5. OBSERVATIONS Vegetation around the residence consists primarily of grassy areas with some small to medium shrubs. The residence does not appear to have a sprinkler system. The surface grades on the north side of the residence appear adequate to drain water away from the foundation. The surface grade on the east and west sides of the residence appears to be relatively flat. The surface grade on the south side of the residence appears to be negatively sloped towards the foundation. Ares of ponding water were observed on the north and west side of the residence. The areas of ponding water are shown on the attached Foundation and Elevation Assessment Plan (SK-1). Some evidence of foundation movement was observed during the inspection which is noted on the attached Foundation and Elevation Assessment Plan (SK-1). The evidence consisted primarily of grade beam cracks, doors out of plumb, sheetrock cracks, and sloping floors. Relative floor elevations were provided by Ram Jack West and spot-checked by Northwest during this investigation. The floor elevations were reportedly taken on February 12, 2021 with a Ziplevel. The Ziplevel is a pressurized hydrostatic altimeter and works by measuring the difference in elevations between the base unit and the handheld unit. The basepoint was reportedly set to 0.0 inch and located near the southwest corner of the residence. Negative elevations referenced are below the basepoint, and positive elevations are higher than the basepoint. The lowest point was recorded near the center of the east exterior wall of the residence. The high point was recorded near the center of the west exterior wall. The elevation differential between the low and high points of the residence was found to be about 4 1/2 inches. These elevations are shown on the attached Foundation and Elevation Assessment Plan (SK-1). RECOMMENDATIONS I recommend a total of thirteen (13) helical steel piles be installed at the residence. Pile locations are shown on the Foundation and Elevation Assessment Plan (SK-1). The steel piling system used should have an evaluation service report (ESR) recognized by ICC-ES showing compliance with the currently adopted International Building Code (IBC). The steel piling system should also P.O. Box 10393 / Eugene, OR, 97440/ 541.393.7363 / WWW.NWENGGROUP.COM j j