Permeable Base Rock (Drainage Base, Open-Graded Base Rock, Permeable Class II Aggregate)
Permeable Base Rock is a free-draining, open-graded aggregate designed for projects where water flow and drainage are critical. Unlike traditional road base, this material contains little to no fines (dust), allowing water to pass through easily instead of compacting into a solid surface.
This makes it the ideal base layer for permeable systems, drainage applications, and water management projects where preventing runoff and pooling is essential.
It is commonly used by contractors, engineers, and homeowners looking to build stable yet highly permeable foundations that meet modern drainage and environmental standards.
Common Uses
Permeable Base Rock is widely used in both residential and commercial projects where drainage and water infiltration are essential.
Primary Applications:
Permeable paver systems (driveways, patios, walkways)
French drains and drainage trenches
Dry wells and infiltration systems
Underdrain base for artificial turf
Erosion control and slope stabilization
Retaining wall backfill (drainage layer)
Parking areas and access roads requiring drainage
Because of its open-graded structure, this material allows water to move freely through the base layer, helping reduce standing water, runoff, and soil saturation issues.
It is especially popular in areas with heavy rain or strict drainage requirements, where traditional compactable base rock would trap water instead of allowing it to pass through.
Material Specifications
Permeable Base Rock Class II is engineered to maximize drainage while still providing a stable foundation layer.
Specs:
Type: Open-graded crushed aggregate (minimal fines)
Size: Typically 1/2” to 1.5” (may vary by quarry)
Composition: Angular crushed rock
Color: Gray (varies by source)
Permeability: High – allows rapid water infiltration
Compaction: Minimal compaction (locks by shape, not fines)
Because this material contains less dust, it does not compact like traditional road base. Instead, the angular rock pieces interlock to create a stable yet porous structure that maintains void space for water to pass through. This balance of strength and permeability makes it ideal for systems designed to handle stormwater, drainage flow, and groundwater recharge.
Key Benefits
Permeable Base Rock offers a unique combination of strength, drainage, and long-term performance, making it a preferred choice for modern landscape and construction projects.
Why choose permeable base rock:
High Drainage
Allows water to flow through quickly, preventing pooling, runoff, and water buildup.
Reduces Flooding & Erosion
Helps manage stormwater by promoting natural infiltration into the ground.
Prevents Water Damage
Ideal under pavers and turf to avoid shifting, heaving, or saturation issues.
Stable Yet Permeable
Angular rock locks together to form a solid base while maintaining void space for drainage.
Low Maintenance
Minimizes mud, standing water, and long-term drainage problems.
Environmentally Friendly
Supports groundwater recharge and meets many permeable system and stormwater compliance requirements.
This material is especially valuable for projects where traditional compactable base would trap water and lead to failure over time.
Delivery & Ordering Information
We offer bulk delivery of Permeable Base Rock across the Bay Area using driveway-friendly dump trucks and larger contractor loads.
Available Load Sizes:
Small Dump Truck:
Approx. 5–7 cubic yards (ideal for residential jobs, tight access, driveways)
Large Dump Truck:
Approx. 17–20 cubic yards (best for contractors, larger projects, job sites)
Important Notes:
One material per load (no mixing)
Dump location must be flat, accessible, and clear of overhead obstructions
Driver will determine the safest dump location on-site
Minimum order quantities may apply depending on location
Because trucking costs fluctuate with fuel prices and distance, pricing is typically quoted with delivery included to ensure accuracy. We recommend placing orders in advance to secure scheduling, especially during peak season.
Frequently Asked Questions (Permeable Base Rock)
What is permeable base rock?
Permeable base rock is an open-graded aggregate with little to no fines, designed to allow water to pass through freely while still providing a stable base layer.
What size is permeable base rock?
It is typically 3/4” to 1.5” clean crushed rock, though sizing may vary slightly depending on the quarry source.
How is permeable base different from road base?
Road base contains fines (dust) that compact tightly and block water flow. Permeable base rock has no fines, allowing water to drain through instead of sitting on top.
Do you compact permeable base rock?
It is lightly compacted or seated, but not fully compacted like road base. The angular rock locks together naturally while maintaining void space for drainage.
What is permeable base rock used for?
It’s commonly used for:
Permeable paver systems
Drainage layers and French drains
Artificial turf base
Retaining wall backfill
Erosion control and stormwater management
How much permeable base rock do I need?
Coverage depends on depth, but as a general guide:
1 cubic yard covers ~100 sq ft at 3” depth
1 cubic yard covers ~75 sq ft at 4” depth
For most permeable systems, a 4–6 inch base layer is recommended.
Does permeable base rock prevent standing water?
Yes. Its open structure allows water to drain quickly, helping eliminate puddles, runoff, and saturated soil conditions.
Can I use permeable base rock for a driveway?
Yes, especially for permeable paver driveways or drainage-focused designs. However, it is typically used under a surface layer rather than as the final driving surface.
