West Seattle ground, weather, and permits
Dense Vashon till commonly caps Seattle’s hilltops, and below it lies pervious sand over Lawton Clay. Rain soaks down through the sand, perches on the clay, and comes out as springs on the hillside. Seattle’s 1999 landslide study names Alki, Beach Drive SW, Admiral Way, 47th Avenue SW, and Pigeon Point as places with many landslides, and finds water involved in nearly all of them. Down in the Duwamish valley, the city’s 2015 plan review notes fill and liquefiable soils.
The Seattle Department of Construction and Inspections (SDCI) decides building, grading, side sewer, and critical-area questions. SDOT permits work in the street and sidewalk, and Seattle Public Utilities sets the drainage rules. The city’s map of environmentally critical areas covers steep slopes, landslide-prone ground, liquefaction, and flood areas, and the Shoreline District reaches 200 feet inland from the water. We look up the map layers for your parcel before we quote.
Nearby, we also build in White Center, Burien, Tukwila, and Normandy Park, and we serve the rest of Pierce and South King County.