Grading, Topsoil & Dirt Work in Seattle, WA

Grading, topsoil and dirt work in Seattle are what decide whether a new lawn thrives or struggles, long before any seed goes down. After construction, yards are often left with compacted subsoil, ruts, leftover gravel and slopes that send water toward the foundation. We fix that with yard grading and land grading, spread screened topsoil where the soil is thin, and shape the surface so runoff heads away from the foundation and leaves the property where it is supposed to. Then we hydroseed, so the job goes from bare dirt to new grass with one crew.

Thin soil over hard till

On western Washington uplands, soils such as the Alderwood series have a gravelly sandy loam surface over dense glacial till, and the USDA puts that dense layer 50 to 100 centimeters down in a typical profile. Construction can strip or bury the darker surface layer and leave the gravelly subsoil on top. Grass planted on that dries out fast in a dry summer and sits wet in winter. A few inches of topsoil, worked into the loosened surface rather than laid on top like a crust, gives roots somewhere to go. On poorly drained ground, WSU's advice is to work in organic material such as compost rather than sand: about 2 inches spread and mixed thoroughly 6 to 8 inches deep. The extension service also notes that soils west of the Cascades are often low in calcium, so a soil test before seeding is worth it.

Grading for winter water

Seattle's wet season runs roughly October through March, and in many yards a perched water table rises close to the surface in winter. Grading cannot change the water table, but it can stop surface water from pooling against a foundation or in the middle of the lawn. We set a gentle fall away from the house, smooth out low spots and direct runoff toward a swale, drain or the street edge where it can leave safely.

Excavation and trenching for drainage

On some Seattle lots, reshaping the surface is not enough to move the water. The same crew that grades your yard digs the drainage too: excavating and trenching for French drains through soggy areas, downspout lines, and shallow swales that carry water around the house. Every dig starts with a utility locate request so buried lines are marked first.

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Topsoil done properly

Topsoil prices are usually quoted three ways: the material by the cubic yard, delivery by the truckload, and spreading labor by the hour. We quote all three as one line so you know the real number. We also tell you how much you actually need. On many lots, two to four inches blended into the top of the existing soil does more good than a thick layer dumped on hard ground.

Land grading for larger lots

On acreage and larger suburban lots, grading moves more material and needs more planning. We set grades with a laser or string lines, shape swales to carry water toward an approved discharge point, and keep the darker surface soil aside to spread back over the finished grade. On sites that need a grading permit or stormwater review, we work from the approved plan rather than eyeballing it.

Wet ground and scheduling

Grading saturated soil smears and compacts it, which is the opposite of what a lawn needs. In Seattle's wet season we schedule dirt work around dry spells where we can, and we keep equipment off soft areas. Fine grading and seeding in early fall, before steady rain sets in, is ideal; summer grading works well too if the lawn will be irrigated afterward.

Leftover construction debris

New lawns fail over buried trouble: chunks of concrete, nails, lumber offcuts, wrapping and pockets of gravel that dry out first in summer. WSU Extension points out that soil left after construction is often infertile subsoil with rocks, lumps and building detritus mixed in. We rake and pick that material out during rough grading, haul it away, and probe the surface so a spray-on lawn is not hiding problems that show up as brown patches in August.

Planting strips and small spaces

Seattle's planting strips between sidewalk and curb are small, often compacted, and surrounded by hardscape and tree roots. We loosen them by hand where machines cannot work, add topsoil to bring the grade even with the sidewalk, and leave a level surface ready for seed.

When grading is done, we can hydroseed the same day or the next, so freshly worked soil is not left bare for a rainstorm to crust over.

Small dirt work jobs we take on

• Filling ruts and low spots after construction or a tree removal
• Removing leftover gravel, concrete chunks and debris before seeding
• Breaking up compaction with a tiller or ripper
• Reshaping planting strips and side yards
• Spreading and fine grading topsoil for new lawns and beds