Is Crushed Concrete A Good Paver Base? Considering The Pros & Cons For Your Hardscape?

Disclosure: We may get commissions for purchases made through links in this post.

Are you planning to install a patio, and you’re wondering if you can use crushed concrete for your paver base? Wonder no more, for we researched this question, and we have the answer for you.

Although it is not the best base material for pavers, it is still a good paver base.

Crushed concrete has several attributes that make it different from other paver base materials. We wrote about them in detail in the succeeding sections. You might want to know about them so that you can decide if you still want to continue using crushed concrete as a paver base.

Read on!

Crushed stone stockpile, Is Crushed Concrete A Good Paver Base? Considering The Pros & Cons For Your Hardscape?

What are the different materials used as paver base?

We talk about the different materials used as a paver base in the sections below so that you can compare each one and decide whether you’d like to stick with crushed concrete or not.

Crushed concrete

A stockpile of rock

Crushed concrete is also called recycled concrete aggregate or RCA. It has the benefit of being more environmentally friendly.

A common material used for paver base is crushed stone. It is made of small stone pieces crushed to a specific size and then screened for uniformity.

Manufacturing crushed concrete uses less energy than crushed stone—creating a smaller carbon footprint. Additionally, using crushed concrete takes away the need to mine virgin materials, crushing them, and transporting them to the site.

Moreover, crushed concrete provides similar performance as crushed stone at a fraction of the cost.

The downside of crushed concrete is that it can be unpredictable because it can be composed of rocks that can be found in the crushed concrete. However, this can be mitigated by checking first with the materials provider and checking the quality of the crushed concrete that they have. This will help you eliminate the unpredictability of concrete and its stone composition.

Crushed stone

We already talked about some of the disadvantages of crushed stone and where it comes from. So, let’s jump to more of the specifics.

Crushed stone is commonly made from dolomite, limestone, basalt, sandstone, and granite. It can come in different sizes, although the best size and shape to be used as a paver base is 3/4-inch and have an angular shape.

Crushed stone is an ideal paver base because it has excellent water drainage and binds very well. It is also easy to work with. The angular surface of crushed stone makes them easy to tamp and vibrate into place, locking with other crushed stones.

Gravel

Gravel being separated using a conveyor

We understand the confusion. Most people call gravel and crushed stone ‘gravel,’ but the two are different materials. And most building material retailers sell them separately.

What’s the difference between gravel and crushed stone?

The two are made from the same types of rocks—dolomite, limestone, basalt, sandstone, and granite. The first difference is where they’re sourced from.

Crushed stones are quarried from mines and come from crushing mother stones. On the other hand, gravel comes from riverbeds, streams, and gravel pits.

Crushed stones became that way because of human intervention. Gravel was created naturally by erosion.

And this brings us to their most important distinctive difference—shape.

Crushed stones have an angular surface and shape. Gravel has a smoother surface and a rounder shape.

What are the advantages and disadvantages of gravel as a paver base?

A wheel barow filled with sand for mixing concrete

Gravel has the same properties as crushed stone when it comes to draining water and permeability. Its primary disadvantage is that it can easily shift when tamped because of its smooth surface. It can be difficult to work with it if inclined too much.

Gravel is more commonly used in landscaping. Its round and polished shapes easily complement gardens.

Sand

Sand is also a popular paver base because of its accessibility and ease of use. It is easy to spread sand over an area, and it responds very well to tamping and compacting.

Unfortunately, sand is not a good paver base material.

It can easily shift and cannot sustain a firm foundation for very long. If the foundation of your paver is uneven at the bottom, the pavers on top will reflect it.

Instead of being used as a paver base, coarse sand is often used with another material as a base.

Concrete sand, known as bedding sand to some, is ideal because it doesn’t trap moisture. It makes it easy for pavers to easily drain water after heavy rain. Good water drainage makes it easy for pavers to maintain their structure over long periods.

Stone dust

This is a powdery material that is made from ground stones. It has a texture that is similar to sand.

It is never used on its own as a base material.

Stone dust and all types of ‘screenings’ have too many dust particles that trap large amounts of water. This prevents the pavers and the base from properly draining water.

Undrained water at the base compromises the ability of the base to distribute and carry compressive loads. This causes shifting and sinking in various areas of the pavers.

It is best to go for a more stable material when choosing a paver base material.

Compacted soil

Compacted sand

Compacted soil is called the subgrade and is what supports the paver base.

Technically, it is possible to lay pavers directly on top of compacted soil. However, this can cause a lot of issues.

Compacted soil has poor drainage. Extended periods of getting soaked in water will cause instability in the structure. This will lead to unevenness in the pavers.

Compacted soil is vulnerable to warping caused by the climate—causing it to freeze and expand in the winter. Once it thaws, the constant exposure to water will cause it to become uneven and soft, sinking the pavers above it.

Like stone dust, it is best to use a different material on top of compacted soil as a paver base.

What are some of the best practices for installing pavers?

Picking a reliable material as your paver base is only one of the different aspects that you need to plan when installing pavers. The structure of your paver base—how well it has been laid out and what material is it made of—will determine whether your patio will last for thirty years or just thirteen months.

Here are some best practices when installing pavers.

Excavate properly

Proper excavation starts with proper planning. Before jumping into the site with shovels blazing, call 811 and set up a schedule for an inspection. This will tell you where the utility lines are located before you start digging.

If your initially planned area coincides with the location of the utility lines, adjust it to avoid the utility area.

Once you know where your utilities are located, it is time to excavate the area. Excavation serves two important purposes—it removes loose dirt from the area that is not good for the structural integrity of the pavers. Additionally, it exposes the underlying soil that will serve as your subgrade.

Dig to correct depth and identify subgrade

Two types of soil are common in the US—granular soil and clayish/cohesive soil.

Granular soil is ideal for subgrade because it drains well, making it a strong subgrade for your paver base. On the other hand, clayish soil makes a weak subgrade because it becomes soft when wet.

The depth is different for these two types of soil. Granular soil needs a 7-inch paver base depth, while clayish soil should have a 9-inch paver base depth.

To get the total depth that you need to dig, add the paver base depth to the thickness of the pavers that you will install, plus one inch for the bedding layer. If the area freezes during winter, double the depth for the paver base.

If the clayish soil is too compact and has high plasticity, it is best to stabilize the soil by mixing type S mortar mix or lime into the clayish soil to change its chemical composition. This will improve its ability to drain water.

Check out SAKRETE type S mortar on Amazon.

Paver base and compacting by layer

After you’ve dug the right depth, pour in your paver base material until you get to a depth of two inches. Spread the layer evenly and compact using a vibrating plate compactor. Add two inches of material at a time and then compact once more.

The Stark USA 61014 2hp plate compactor with 2000 lbs. of force is available on Amazon.

Install bedding sand properly

Make sure to install your bedding sand properly. That may just be an inch of depth, but that layer is what will make your pavers settle firmly. Screed your bedding layer properly.

Improper installation can create dips that will cause sunken areas when pavers are installed.

Conclusion

Crushed stone stockpile

Crushed concrete makes a good paver base if you pick a good quality batch that has more stable rocks in the mix.

If you enjoyed reading this article, why not check out the two articles below:

How Thick Should an Asphalt Parking Lot Be?

Can You Put Rock Salt On Pavers?