Gravel, Stone and Soil for San Juan County, WA
Washington Rock Supply sells gravel, stone and aggregate delivery in San Juan County, WA. The material to know here is 5/8 minus, the crushed surfacing top course that packs hard and sheds water.
San Juan County sits on the Puget Sound lowland, where a dense till cap sits over sand and the water table stays close to the surface all winter. That ground shapes what you order.
Delivery across San Juan County
You order online and pick a quantity by the ton or by the yard. Each product page has a calculator if you want to size the load before you check out.
Choose a delivery date at checkout, and a dump truck tips the load on site. Bulk delivery reaches Friday Harbor, Blakely Island, Eastsound, Lopez Island and Olga.
The truck tips the material in one pile. Plan where that pile lands before the truck arrives, because the driver does not spread or move it.
Materials delivered in San Juan County
Order by the local name. A Washington yard knows 5/8 minus, drain rock and crusher dust, and the same stone goes by inch sizes on the order sheet.
5/8 minus is the Washington default surfacing course. It is crushed rock with the fines left in, so it packs hard and sheds water instead of soaking it up.
That section sets two gradings: base course at a 1 1/4 inch top size and top course at a 5/8 inch top size.
Contractors shorten those to CSBC and CSTC and order them as 1 1/4 minus and 5/8 minus. Other sections cover gravel base, gravel backfills and riprap.
Order 5/8 minus for a driveway, a parking pad or a shed slab. Order 1 1/4 minus for the structural course below it on soft wet ground.
For drainage, order drain rock or 3/8" Crushed Stone. Both are washed, so water moves through them instead of sitting.
For bedding under pavers, order crusher dust. For a firm path, order 1/4 minus.
For long rural drives, order driveway gravel.
Rounded stone is a separate family. Natural Pea Gravel suits play areas and planting beds, and Washington River Rock suits dry creek beds and splash pads.
Ground conditions across San Juan County
Across the Puget Sound lowland, the ground is glacial material laid down by the Vashon ice sheet. A dense till cap sits on top, and its lower part is hard enough that crews call it hardpan.
Below the till is advance outwash sand, and below that the silt and clay of the Lawton beds. Recessional outwash gravel fills the valley floors.
Perched water is the driver here. Rain soaks the loose upper soil, reaches the dense till and stops, so the water table sits close to the surface all winter instead of draining away.
Anything built on till needs the water taken sideways to daylight. That is why footing drains and washed drain rock do so much of the work on this ground.
Bluff failure is the erosion pattern in this part of the state. Winter rain perches where outwash sand meets the clay below it, and the same perched water undercuts cut slopes and fill on a smaller scale.
Riprap protects shorelines, streambanks, culvert outfalls and cut slopes.
The wet season runs October through April. Under the state stormwater manual for western Washington, exposed soil must be stabilized within two days in that window against seven days in summer.
Base, paving and paver work is scheduled for the dry months, and winter work needs the grade kept covered. Mild, wet winters mean the ground seldom freezes deep, so it is saturation rather than frost that softens a base.
A drive that was firm in August can rut in February. Frost depth is set by the local building official, and published figures elsewhere in the region run 12 to 18 inches.
Choosing the right material
Start with the job. A driveway takes 5/8 minus over 1 1/4 minus.
A patio takes crusher dust for bedding. A drain takes washed stone with no fines in it.
Island County shares this ground region. Its soil is the same Vashon till over advance outwash sand and Lawton beds, so the base and drainage choices carry over unchanged.
Whatcom County and Skagit County each span more than one ground region. Both include the Puget Sound lowland and also reach into the Cascade Range and the east-slope valleys.
That difference matters when a job sits outside the lowland. The lowland ground is glacial till and outwash, while the mountain and east-slope ground is a different material to build on.
On lowland till, plan for perched water and a drainage layer. Minus products compact into a base, and clean or washed products drain.
Keep the two apart. A minus product holds water back, and a clean stone will not pack into a surfacing course.
Match the material to what the ground is doing.
Order 5/8 minus for San Juan County jobs
5/8 minus is the surfacing course this ground is built on, and it is the place to start for a drive, a pad or a slab. Pair it with 1 1/4 minus underneath, and add drain rock where perched water needs a way out.
Order online when you are ready.