Base Course
(1¼” Minus)

Base Course
(1¼” Minus)

PRODUCT CODE: 5990-1 or 5990-3
PRODUCT ORIGIN: King Creek Pit and Kapowsin Quarry
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Product Description
Crushed Surfacing Base Course (CSBC) is a crushed rock product containing minus (also known as fines). It’s a state-spec gravel made up of rock pieces up to 1¼” in diameter. The fines help the product pack down tightly and stay in place when compressed. CSBC performs well in wet conditions and provides stability in muddy conditions.

CSBC is manufactured at both Kapowsin Quarry (5990-1) and King Creek Pit (5990-3). The Kapowsin Quarry version is made from quarried basalt rock while the King Creek Pit version is made by crushing streambed rock. Both products are fractured and angular.

CSBC meets WSDOT Standard Specifications 9-03.9(3) for grading:

  • 99–100% passing the 1¼” screen
  • 80–100% passing the 1″ screen
  • 50–80% passing the 5/8″ screen
  • 25–45% passing the #4 screen
  • 3–18% passing the #40 screen
  • up to 7.5% passing the #200 screen

Our CSBC also meets or exceeds all quality test requirements for fracturing, sand equivalency, abrasion, and degradation.

Product Applications
Like the name suggests, base course is typically used as a base layer for gravel driveways and parking lots or as a subbase for paved surfaces. It’s often topped with Crushed Surfacing Top Course (CSTC).

CSBC is an ideal gravel for roadways that are busy or are used by heavier equipment. CSBC can also be used as a structural base for retaining walls.

Similar Products
1¼” Minus Road Base (Grade 1 Tailings) (5961-1) is a more affordable, non-spec alternative to CSBC.

CSTC (5/8″ Minus) is a good choice for driveways or paths used by cars and light equipment.

We can also manufacture 1¼” Minus Shoulder Rock.

Helpful Tips
If you’re stumped about whether to use clean or minus material, check out our “Clean v. Minus” guide.

You can also refer to our popular article and video, “Choosing the Right Rock: Comparing Crushed Rock Sizes and Types.”

About Base Course
Base Course refers to a bottom layer of material that provides foundational support to driving surfaces or structures. It’s usually installed on top of a prepared subgrade (earth layer) or subbase material. It provides support to the “surface course,” which is the topmost layer of gravel and/or asphalt and concrete. Both of our base course products are 1¼” minus products. Our Crushed Surfacing Base Course (CSBC) is made to a specification dictated by the Washington State Department of Transportation (WSDOT) while our tailings are a more affordable non-spec product.

Pricing & Availability
Minimum $35.00 purchase required on all materials. Check pricing and availability by requesting a quote online.

Material Spreading
Prices quoted are for material delivery only. Drivers do their best to dump material evenly when requested. However, Washington Rock cannot guarantee that this will result in an even or desirable distribution of material. Customers must supply the equipment and labor necessary to finish projects.

Minimum Delivery Quantity
Our minimum order quantity for deliveries is 10 cubic yards. Do you need less than that? Find a local supplier here.

PRODUCT CODE: 5961-1
PRODUCT ORIGIN: Kapowsin Quarry
GET A QUOTE

Product Description
1¼” Minus Road Base (Grade 1 Tailings) are a less expensive, non-spec alternative to CSBC. Like CSBC, tailings are a gravel product made up of fines and rock pieces up to 1¼” in diameter. The fines help the product pack down well. This product is manufactured at Kapowsin Quarry.

Product Applications
Like CSBC, tailings can be used as a base layer for gravel driveways and parking lots or as a subbase for paved surfaces (concrete, asphalt, etc.).

Similar Products
Grade 2 Tailings (5962-1) can also be made to order for commercial projects for use as a road base, structural fill, and trench backfill.

About Base Course
Base Course refers to a bottom layer of material that provides foundational support to driving surfaces or structures. It’s usually installed on top of a prepared subgrade (earth layer) or subbase material. It provides support to the “surface course,” which is the topmost layer of gravel and/or asphalt and concrete. Both of our base course products are 1¼” minus products. Our Crushed Surfacing Base Course (CSBC) is made to a specification dictated by the Washington State Department of Transportation (WSDOT) while our tailings are a more affordable non-spec product.

Pricing & Availability
Minimum $35.00 purchase required on all materials. Check pricing and availability by requesting a quote online.

Material Spreading
Prices quoted are for material delivery only. Drivers do their best to dump material evenly when requested. However, Washington Rock cannot guarantee that this will result in an even or desirable distribution of material. Customers must supply the equipment and labor necessary to finish projects.

Minimum Delivery Quantity
Our minimum order quantity for deliveries is 10 cubic yards. Do you need less than that? Find a local supplier here.