Pavers

Open-Graded Aggregate

Open-graded aggregate is aggregate with a size distribution that leaves relatively open voids between particles compared with a densely packed mix containing more intermediate sizes and fines. It can serve particular drainage and storage functions in designed assemblies.

Clean washed angular crushed stone on a tray with visible spaces between particles and minimal fine sand, product photograph.
AI-generated educational image. Assigned location metadata: North Port, FL. This is not a documented local project or an installation detail.

Voids are part of the intended system

Permeable pavement can use open-graded layers to pass and store water. Their material sizes and arrangement follow the system design. Do not assume a loose gravel pile or any clean-looking stone is the specified product. Ask for the relevant material description and delivery identification, along with the role of each layer.

Two separate small trays of aggregate on a workbench, one clean single-sized angular stone and one dense mix with fines.
AI-generated educational image. Assigned location metadata: North Port, FL. This is not a documented local project or an installation detail.

Do not substitute by appearance

Dense-graded base and open-graded reservoir materials serve different purposes. Changing one for the other can affect support, drainage and interaction with neighboring layers. A permeable-pavement detail should be reviewed as a complete system, including joints, bedding, reservoir and outflow. The word gravel alone leaves these differences unexplained.

A practical homeowner example

A homeowner compares two base quotes, one for conventional paving and one for a permeable system. The contractor explains why the materials and layer functions differ instead of comparing only the delivered tonnage.

This is an illustrative planning scenario, not a report of a particular West Coast Screening project.

Questions to bring to an estimate

  • Identify the affected area, intended traffic and existing pavement system.
  • Keep unit, joint, bedding, base and soil questions separate.
  • Ask how drainage and perimeter restraint are included in the scope.

Frequently asked question

Is open-graded stone the same as ordinary road base?

Not necessarily. Gradation and intended function differ. The actual material specification should be compared rather than relying on a familiar trade nickname.

Related glossary terms

For the broader vocabulary, return to the pool cage and screen-enclosure glossary.

Authority sources and further reading

Use these sources within their scope. Manufacturer information applies to the identified product; research and general guidance do not establish a rating or an approved repair for an individual project.