Buy Bulk Gravel, Sand and Soil in Washington

Washington Rock Supply brings bulk gravel and aggregate delivery across Washington, ordered online by the ton or by the yard. The material this ground is built on is 5/8 minus.

West of the Cascades, most of the year's rain lands between October and March on ground that is already saturated. Dense glacial till holds a perched water table close to the surface, so a drive or a pad needs a base that sheds water rather than trapping it.

East of the crest the problem runs the other way: seven to nine inches of rain a year in the driest parts, fast-draining flood gravel and basalt, and runoff that arrives all at once.

Materials Delivered Across Washington

5/8 minus is crushed rock with the fines left in, so it packs hard and sheds water instead of soaking it up. Contractors and quarries also call it crushed surfacing top course, or CSTC.

It is the default surfacing course for driveways, parking pads, shed and shop slabs. The larger structural course below it is 1 1/4 minus, or crushed surfacing base course, CSBC, with a 1 1/4 inch top size.

Minus means the crusher fines stay in, so the rock compacts and holds. Clean or washed means the fines have been taken out, so the stone drains.

That split is the most useful thing to get right on a Washington order.

Washed stone covers the drainage side: 3/4 clean for trench backfill and pipe surround, and drain rock, sold as 7/8 clean, for footing drains and infiltration trenches where a perched water table sits on till.

Rounded stone is a separate family. Washington yards file it under round rock rather than crushed, and it is used for dry creek beds, splash pads and rain garden armour where a smaller stone would be carried off.

Sand, soil and mulch finish the list: mason sand for mortar and stucco, screened topsoil for lawns, and beauty bark, the Washington trade name for landscape bark, for beds and tree rings.

Ground and Climate Across Washington

Western Washington runs on the wet season calendar. Under the state stormwater manual for western Washington, exposed and unworked soil has to be stabilized within two days from October 1 through April 30 and within seven days from May 1 through September 30.

That is why base and paving work is pushed into summer. Eastern Washington treats October 1 through June 30 as its wet weather season and loses the deep winter to frozen ground.

Ground conditions differ sharply across the state. In the Puget Sound lowland, the Vashon ice sheet left a dense till cap over advance outwash sand, with recessional outwash gravel filling the valley floors and soft silt in the river deltas.

On the Olympic Peninsula and the Pacific Coast, thin stony soil sits over uplifted marine rock, with deep organic forest soil in the west-side valleys and sand, peat and tidal silt along the bays.

Southwest Washington, the Chehalis valley and the Willapa Hills carry river terrace silt and gravel, weathered marine sandstone and siltstone, and volcanic ash and reworked lahar deposits on ground draining Mount St. Helens.

East of the crest, windblown loess sits over Columbia River basalt. The Ice Age floods stripped the loess off in the Columbia Basin and left the basalt bare in the channeled scablands, and dropped sand and gravel bars in the coulees.

In the Palouse, that same windblown silt escaped the floods and is piled into rolling hills, fine and deep and easily moved. In the Spokane Valley, the ground is cobbles, gravel and sand dumped by the Missoula floods.

Washington has no statewide frost depth table. The state residential code requires exterior footings at least 12 inches below undisturbed ground and leaves the frost line to the local jurisdiction.

Published figures run from 12 inches in the western lowlands through 18 inches in King and Grant counties to 24 inches at Spokane and in Okanogan County. Confirm the local number with the county or city building department.

Where We Deliver in Washington

Washington Rock Supply delivers across Washington, from the Puget Sound lowland and the Olympic Peninsula to the Columbia Basin, the Yakima Valley and the Inland Northwest.

Counties covered include King County, Pierce County, Snohomish County, Spokane County, Clark County, Thurston County, Kitsap County, Yakima County, Whatcom County, Benton County, Skagit County and Cowlitz County.

That covers the wet western valleys, the Columbia Gorge, North Central and Northeast Washington, the Palouse and Southeast Washington. Wherever the site sits in the state, the order is placed online and a dump truck tips the load on site.

How to Order and Size a Load

Order online and choose your quantity by the ton or by the yard. Each product page has a calculator to help size the load.

Pick your delivery date at checkout. The truck arrives and tips the material in one pile on site, so have the drop spot clear before it lands.

Order Bulk Gravel and Aggregate Across Washington

Washington Rock Supply delivers bulk gravel, sand, soil and mulch across Washington, from the Puget Sound lowland to the Columbia Basin and the Palouse.

Order 5/8 minus, 1 1/4 minus, washed stone, sand or topsoil online by the ton or by the yard, and pick your delivery date at checkout.