Essential Steps for Concrete Driveway Base Preparation

If you want your driveway to look great and last long, proper concrete installation is a must! Learn how to prep your driveway for concrete repair or replacement!
Jimmy Soldatos
Jimmy Soldatos
Last Update:
October 21, 2021

Any pavement project consists of several components. Base material is one of the most important. Without a sturdy base, your new driveway won't last as long. In this post, we'll go over the importance of base material and professional installation when it comes to pavement projects.

Materials and Tools Required for Base Preparation

There are specific materials and tools required for your concrete driveway’s base layer. The base layer of your driveway is made out of rock, gravel and sand. 

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Step 1: Site Preparation: Clearing and Grading the Area

Even before preparing the base layer for your concrete driveway you need to make sure that the area has been cleared of vegetation, large rocks and stones. Before you do any digging, however, call 811 - the national call-before-you-dig phone number. 

If your driveway is on flat ground, then you do not have to worry about grading. However, if your driveway site is not level, you will need to have it graded. You can choose to grade your site to be flat or you can opt for your driveway to be on a specific type of slope. Grading allows you to reshape the land at your construction site by raising or lowering the ground level, or by adding or removing slopes. 

Step 2: Marking and Layout: Determining the Dimensions of the Driveway

To mark the outline of your new concrete driveway, you will need wooden stakes and string. You should pound in the wooden stakes at four foot intervals along the border of your driveway site.

Step 3: Excavation: Digging Out the Area for the Base

Before you begin constructing the base of your concrete driveway, you will need to dig out the area for the base. You should dig down to a depth of about 3 to 5 inches for the concrete and another two inches for the base layer below the concrete. Then, smooth out the ground with the flat side of your rake to ensure a level work site.

Step 4: Compaction: Ensuring a Sturdy and Stable Base

Once you have your site cleared and dug out to your desired depth, you will need to compact the ground to the point where you can hardly see footprints anymore. Use a hand or mechanical tamper to pack down the soil to this degree. 

Step 5: Adding Drainage: Preventing Water Buildup and Damage

Proper drainage is essential to making sure your concrete driveway lasts for decades. One way to achieve proper drainage is to build your driveway on a slight gradient, which allows the water to drain. 

Another option is to build a trench drain which is a linear drain that acts as a gutter for your driveway. Keep in mind these trench drains should direct the water to a soakaway or other area that can absorb the water.

Step 6: Installation of Forms: Creating a Barrier for the Concrete

Now that you’ve prepared the ground and have a good base layer for your concrete driveway, the next step is to build the forms that border the area where the concrete will be poured. Wood is most often used for concrete forms. You will need straight and flat pieces of wood to use as forms. 

Step 7: Adding Gravel: Providing Additional Support and Drainage

To ensure good drainage and support for the concrete, pour 2 inches of gravel all over your site. Then tamp down the gravel to make sure that it is packed down and check to make sure it is even and flat. In many cases, a good gravel base layer is the key to your concrete driveway lasting as long as possible. 

Step 8: Final Inspection: Ensuring a Smooth and Even Surface

The final step before pouring the concrete into your forms is to make sure that the surface is smooth and even. This will ensure the poured concrete has the best foundation and the best chances for lasting decades.

Concrete Layers

The build starts from the bottom up, so the first component to consider is the subsoil. Subsoil characteristics combined with customer requirements determine the characteristics of the pavement to be constructed. That consists of various layers, ranging from embankment materials on large infrastructure projects, to a few base layers on small, residential projects.

The bottom layers are labeled base, subbase, and subgrade. These are made out of rock, gravel, and sand. The top layers can be poured cement, concrete pavers, or different paving materials.

It is of the utmost importance to note that these layers, laid on the existing subsoil, act in unison. The characteristics of any of these have an impact on the overall strength and longevity of the final pavement construction. Thus, the optimal pavement construction in terms of quality and value is achieved by selecting proper materials and their thickness in relation to one another.

You can think of it in terms of a series of springs. Imagine three springs on top of each other and a weight on top of the springs. If one of those springs is weak, then we need to make the others stronger to hold that weight. Conversely, even if we have one very strong, expensive spring, the whole system will collapse if the others are too weak.

Crack in a concrete slab due to improper base layer preparation

To add to this equation, pricing for each layer varies significantly. Reinforced concrete is the most expensive by far, while the gravel base layer is the cheapest. So, the variance in depth of each layer carries a key significance in the total price for the customer. That means that of all the different options for building a quality paved surface, there are just a handful of them that offer the highest value as well as top quality.    

Since subsoil characteristics are a product of natural rock decomposition for any given area, they are impossible to change. They are also somewhat difficult and expensive to measure and analyze for a small, residential project. Thus, some precautions must be taken in designing a paved surface for a home so that it conforms to the highest standards of quality and longevity.

The only way to ensure proper quality, while maintaining a reasonable price, is by creating a quality base layer that will ensure a solid, flat surface for final pavement installation. While the final concrete layer is the one that will be visible to everyone, and the most expensive part of the construction, its longevity will be seriously compromised by an improper base layer.

Concrete Layers

Concrete layer thickness is the main driver of total project price, but even a thicker layer of concrete will likely crack and separate if the ground shifts. California has frequent earthquakes. Building a thicker concrete layer to cover all eventualities is at best ineffective, and will end up costing the customer much more than necessary.

A properly compacted, thicker, layer of base rock on the other hand, is the optimal way of ensuring that concrete is poured onto a hard, flat surface, which will remain stable for decades to come. Combined with quality reinforced concrete and proper drainage, this will create a durable, high quality pavement in tune with modern engineering practices.

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