Seattle
Landscaping & Hardscaping in West Seattle, Seattle
Quick answer
West Seattle is a glacial peninsula with a plateau in the middle and slide-prone bluffs on both edges. Most lots sit on Alderwood soil over till hardpan, so drainage drives every design. We build walls, patios, steps, fencing and irrigation across the peninsula, roughly thirty minutes from our Kent shop.
- From our Kent shop
- about 30 minutes
- ZIP codes served
- 98106, 98116, 98126, 98136, 98146
- Licensed in WA
- Bonded & insured
West Seattle is not really a neighborhood. It is a glacial upland peninsula about the size of a small city, hung off the rest of Seattle by one high bridge and one low one, and it has three completely different edges. The Puget Sound side runs from Alki around Beach Drive to Fauntleroy as a bluff. The east side drops into the Duwamish valley through Pigeon Point, Riverview and Highland Park. The middle, from the Admiral District south through the Alaska Junction to Gatewood and Arbor Heights, is a broad plateau sitting between two hundred and three hundred feet. Those three edges get worked differently, and pricing a project here starts with knowing which one your lot is on.
The housing arrived in waves you can read straight off the street. Admiral and the Junction filled with Craftsman bungalows and foursquares through the 1910s and 20s, on platted five-thousand-square-foot lots with alleys behind them. Highland Park, South Delridge and the blocks toward White Center took fast wartime housing for Boeing in the early 1940s, small footprints on flatter ground with no landscaping budget at the time and not much added since. Beach Drive, Seaview and Gatewood picked up view ramblers and daylight basements through the 1950s and 60s. Since roughly 2015 the arterials, California Avenue and Delridge Way in particular, have absorbed a heavy load of townhouse and rowhouse infill where the back yard is simply whatever was left over after the building envelope.
The requests follow the terrain. On plateau lots people want a back yard they can use: a paver patio that stays flat, a fire table, cedar fencing, a lawn small enough to be honest about. On the sloped lots, and there are a great many of them, the ask is grade. Terraces, steps, a wall to hold the cut behind the garage. The single most common hardscape call we get on this peninsula is a failing timber wall. Pressure-treated 6x6 and railroad-tie walls installed in the 1970s and 80s are at the end of their service life everywhere out here, and they almost always fail leaning outward with the soil already moving behind them. Replacing one is a drainage job at least as much as it is a block job, and anybody who quotes it as just block has not looked behind the wall.
What the shovel finds is Alderwood series soil over Vashon till: eighteen to thirty inches of gravelly sandy loam sitting on a hardpan that water will not pass through. That is why so many West Seattle back yards are soup in February and concrete in August, and it is why every base section we build here drains to daylight rather than into a dry well that has nowhere to give. Cobbles and glacial erratics come up constantly. On the older streets we hit buried heating oil tanks, clinker brick and mixed demolition fill in the top three feet. Along Delridge the ground changes character because Longfellow Creek runs that valley, partly piped and partly open, and the subgrade near its course stays wet year round. Out on the bluff edge above Beach Drive the till gives way to loose Esperance sand that will not hold a vertical cut for an afternoon.
Access here is easier than in the north-end Seattle neighborhoods, though it is not free. Many older blocks have alleys, which is how we put a mini excavator in a back yard instead of running wheelbarrows all week. Streets on the bluff are narrow, steep and often parked solid, and a handful of Beach Drive addresses have no legal place to set a dump trailer at all. The bridge closure from 2020 to 2022 taught everyone on this peninsula what the detour routes cost, and we still schedule material deliveries around the low bridge and the First Avenue South Bridge rather than assuming a clean run. Design happens in our own office and our crew self-performs the hardscape, so the person who drew the wall is answerable for the base under it. Planting leans on what tolerates a shaded, wind-exposed maritime lot: sword fern, salal and evergreen huckleberry under mature Douglas fir, vine maple and Japanese maple for structure, hydrangea and rhododendron on the sheltered sides of the house, kinnikinnick and lavender where the salt wind comes straight off the Sound at Alki. Irrigation runs on Seattle Public Utilities water behind a tested backflow assembly, zoned so the baking south slope and the wet shade under the firs are never on the same clock.
Ground conditions in West Seattle
West Seattle is a Vashon-age glacial upland, so the plateau from Admiral through the Junction to Arbor Heights is Alderwood series gravelly sandy loam over dense till, typically with hardpan somewhere between eighteen and thirty inches down. Water does not infiltrate through that contact. It perches, moves laterally and shows up as a soggy lawn or a wet garage slab in the wet half of the year, which makes positive drainage and a drain line to daylight the deciding detail on almost every patio and wall we build here. Cobbles and the occasional glacial erratic are routine in the dig. The two edges behave differently. Along the Sound from Alki around Beach Drive to Fauntleroy, permeable Esperance sand sits above the till, groundwater emerges at the contact, and the bank above it is mapped by Seattle for steep slope and landslide hazard for long stretches. That sand will not stand in a vertical cut, so excavations get benched or shored. On the east side the Duwamish valley wall through Pigeon Point, Riverview and Highland Park is similarly steep and similarly mapped. In the Delridge corridor the subgrade stays wet year round near the piped and daylighted reaches of Longfellow Creek. In the pre-1950 blocks we regularly find buried heating oil tanks, clinker brick, coal ash and mixed demolition fill in the upper three feet, and on the newer townhouse lots the native profile is gone entirely, replaced by compacted construction subgrade.
Permits
West Seattle permits through the City of Seattle, primarily SDCI for construction and SDOT for anything touching the right of way. Retaining walls over 4 feet measured from the bottom of the footing to the top of the wall need a building permit with stamped structural engineering, and a wall of any height that carries a surcharge, meaning a slope, a driveway, a parking pad or a structure bearing above it, is treated as an engineered wall rather than a landscape wall. The peninsula has a lot of Environmentally Critical Area overlay on it. Seattle maps steep slope areas at 40 percent grade or greater with at least ten feet of relief, plus separate landslide-prone and potential slide areas, and those overlays cover much of the Sound-facing bluff from Alki to Fauntleroy as well as the Duwamish valley wall behind Pigeon Point and Highland Park. Inside an ECA a geotechnical report is normal rather than exceptional, grading thresholds drop, and the review schedule lengthens. Seattle stormwater rules currently pull in projects that add or replace roughly 750 square feet or more of hard surface, which a mid-sized patio plus a walkway can reach faster than people expect. Seattle also requires a permit to remove most sizeable trees on developed residential lots under its 2023 tree ordinance, with the removal work performed by a registered tree service provider. Waterfront lots at Alki and along Beach Drive fall under the Shoreline Master Program within 200 feet of the ordinary high water mark. Thresholds and overlay boundaries change and are parcel-specific, so we confirm the applicable rules with the city at permit time before a layout is finalized.
Neighborhoods we work in
- Alki
- Admiral District
- The Alaska Junction
- Genesee Hill
- Gatewood
- Fauntleroy
- Arbor Heights
Services we offer in West Seattle
West Seattle: common questions
Does my West Seattle retaining wall need a permit?
Height is only half the question. Seattle exempts walls up to 4 feet measured from the bottom of the footing to the top of the wall, but that exemption disappears the moment the wall carries a surcharge, which includes a slope above it, a driveway, a parking pad or a house foundation bearing nearby. On the bluff blocks the Environmentally Critical Area overlay adds a second layer, and a geotechnical report is usually required regardless of wall height. We measure the actual wall, look up the parcel overlays, and tell you which category you are in before anyone starts drawing.
My old timber wall is leaning. Can it be repaired?
Almost never, and the reason is what is behind it rather than what you can see. The 1970s and 80s railroad-tie and 6x6 walls all over West Seattle failed because water was never given a way out, so the soil behind them saturated and pushed. Straightening the face does nothing about that. What we do instead is take the wall out, cut a clean bench into the till, build a compacted base, set segmental block from Mutual Materials, Allan Block or Basalite with proper geogrid where the height calls for it, and put drainage rock and a perforated drain to daylight behind the whole run.
Why is my back yard soggy all winter and rock hard in August?
That is the till hardpan, and it is the defining soil condition of this peninsula. You have a shallow layer of Alderwood loam sitting on dense glacial till that water cannot pass through, so winter rain perches on the hardpan and stalls, and in summer the shallow layer above it dries out completely. The fix is not more topsoil. It is grade and a drainage path: getting surface water moving toward an outlet, running a drain to daylight instead of a dry well, and building any base section with drainable rock rather than sand that will hold water against the pavers.
Can you build on a bluff lot above Beach Drive or Alki?
Yes, with a geotechnical engineer involved from the start. Above the beach the profile is permeable Esperance sand over impermeable till, groundwater comes out of the slope at the contact, and Seattle maps most of that band as landslide-prone. Loose sand also will not stand in an open cut, so the excavation gets benched or shored rather than dug vertical. Slope work here is real engineered construction, the report is part of the permit rather than an add-on, and we scope and price it that way from the first visit.
How do the bridges affect your scheduling and drive time?
We are about thirty minutes from our Kent shop to most of the peninsula outside peak hours, and material comes over separately from the crew truck. After the high bridge closure between 2020 and 2022 we stopped assuming any single route is available on any given day, so deliveries get routed with the low bridge and the First Avenue South Bridge as live alternates and heavy loads are scheduled off-peak. On the bluff streets we also confirm ahead of time where a truck can legally stage, because several Beach Drive addresses have no parking room in front of them at all.