Install guide · 2-minute read
Open-graded vs dense-graded base
Which base to put under your pavers, and why.
The short version
A dense-graded base (¾" road base) compacts hard and sheds water off the surface. It's the long-standing standard under sand-set pavers. An open-graded base (clear crush, no fines) lets water soak down through the paving. It's used under patios and walkways, and it's the base for permeable paver systems now being specified for driveways, parking areas and commercial projects. Which one you need depends on the paver system and the project spec.
| Dense-graded | Open-graded | |
|---|---|---|
| What it is | Crushed stone with fines (¾" road base, MMCD) | Washed crushed stone with no fines (clear crush) |
| Water | Sheds it, so the surface slopes to drain | Lets it soak down into the base |
| Bedding layer | 1" of bedding sand | About 2" of small clear stone |
| Joints | Sand or polymeric sand | Small clear stone for permeable pavers, or sand on residential patios |
| Typical uses | Patios, walkways, driveways, streets | Patios and walkways, and permeable driveways, parking and commercial work built to spec |
| Upside | Strong, proven, easy to get flat | Manages stormwater, less frost heave, and wet weather won't hold up the job |
| Watch for | Compaction: it needs 98% Standard Proctor | Joint maintenance, so material doesn't clog or wash out |
Dense-graded base
This is the classic base under interlocking pavers with sand joints. Compact it in layers to 98% Standard Proctor: at least 4" under patios and walkways, 6" under residential driveways, and more on clay or wet soil. The fines lock it together, so water runs off the surface instead of through it. Slope the paving at least 2%.
Open-graded base
Clear stone has room between the stones for water. That's why it sits under permeable pavers and why more projects are using it.
- Permeable pavers (driveways, parking and commercial). The joints are filled with small clear stone instead of sand, so rain drains straight through. A typical build is about 2" of small clear stone as bedding, about 4" of larger clear stone as the base, and a subbase of 2" to 3" stone where vehicles or stormwater storage call for it. Driveways start at about 6" of base, and thickness is set by the design for traffic and water. Follow the project specification.
- Sand-set pavers on an open-graded base (patios and walkways). Industry research finished in 2025 supports this for residential foot-traffic areas like patios, pool decks and walkways. Line the dig with geotextile fabric, add a drain pipe where the soil drains poorly, and compact the stone. Joint sand washes down into the stone over time, so top up the joints when they drop more than ½".
Why permeable is catching on. Rain soaks into the ground instead of running into storm drains, which cuts flooding and pollution. Some municipalities encourage it for stormwater control. The trade-offs are a higher upfront cost and regular joint cleaning, by sweeping or vacuuming, to keep it draining.
What to get from us: ¾" road base for dense-graded bases. For open-graded, ¾" clear crush for the base and 9mm clear crush for bedding. Joint stone depends on the paver joint width, so check the paver maker's recommendation. Call 604-986-5279 and we'll help you match the spec.
Summarized from Concrete Masonry & Hardscapes Association (formerly ICPI) and Allan Block installation guidance. Follow the manufacturer's instructions and any engineered plans for your project.