Creating a durable Interlock Driveway for a Beautiful Curb Appeal

Interlocked driveway not only enhances the curb appeal of your property but also offers a durable solution for your vehicle's daily wear and tear. However, the key to a long-lasting interlocked driveway lies in its foundation. Proper preparation and the right materials are essential to prevent sinking and ensure efficient drainage. In this blog, I will guide you through the crucial steps and some of the materials needed to lay an enduring interlocked driveway.

Step 1: Planning and Design

Before diving into the excavation, we will take the time to plan your driveway. We will consider the size, shape, and pattern of the interlock you want. We will have to think about the load it will bear over time, as this will influence the depth, type of materials, and price required for a proper base. Once we agree on a design and the types of materials including the stones you chose we move to the next step in the process which is the excavation

Step 2: Excavation

This second step is the excavation of the area where the driveway will be laid. The depth of excavation depends on several factors, including the climate (freeze-thaw cycles) and the soil type. A general rule is to excavate to a depth of at least 12 inches. Anything less and you will run into caving areas a year or two after the interlock has been laid. Certainly, if you are parking a truck, trailer, or small boat the depths and type of aggregate materials become critically important.  To start with this depth allows for a substantial base that can support the driveway and prevent sinking.

Step 3: Grading for Drainage

Proper grading is critical to ensure water runs off the driveway, preventing pooling and potential damage. A slight slope away from your home or garage, generally a 1% to 2% grade, is sufficient for effective drainage. But consideration must also be given to the surrounding grade immediately next to the driveway

Step 4: Laying the Base Material

Now moving on the this critical next step of laying the base material. The base material is the cornerstone of your driveway's integrity. It provides a sturdy foundation, ensuring the surface remains level and free from sinking.

Sub-Base Layer

The first layer, known as the sub-base, is typically composed of crushed stone or gravel. The size of the stones should range from about ¾ inch to 1 ¼ inch clear stones. This layer should be approximately 6 to 8 inches thick. It's crucial to compact this layer thoroughly, with a tamper, after every two inches of materials are laid to enhance its load-bearing capacity.

Base Layer

Above the sub-base, a finer aggregate is used for the base layer, often consisting of limestone screenings or HPB stones. This layer should also be around 2 ½ , 3, to 4 inches thick and needs to be compacted as well. We may also use in your base layer, as the very top layer, about 1 to 1 ½ inches of concrete sand. The concrete sand can act as a cushion for the pavers and aids in the final leveling process. Much would depend on the type of interlock pavers we are using in your home project.  

Choosing the Right Base Material: HPB vs. Limestone Screening

When it comes to selecting the base material for your interlocked driveway, the debate often boils down to High-Performance Bedding (HPB) and limestone screening. While both materials have their merits, HPB stands out as the superior choice for several reasons, particularly in terms of drainage and durability. Here's why we recommend HPB for your driveway project.

High-Performance Bedding (HPB)

HPB is a revolutionary base material that consists of ¼ inch angular chips and fine dust. One of the standout features of HPB is its self-compacting nature, which means it settles into place without the need for mechanical compaction. This property not only makes it easier to work with but also ensures a more stable base for your pavers. Nevertheless, we still compact it for a perfect level and stone fit.

Superior Drainage

The angular shape of HPB allows for excellent water drainage, making it an ideal choice for areas that experience heavy rain or snowmelt. Unlike limestone screenings, which can compact over time and potentially hinder water flow, HPB maintains its permeability, ensuring that water is effectively directed away from your driveway and foundation.

Durability and Stability

HPB provides a stable and durable base that resists shifting and settling. This means your interlocked driveway will maintain its integrity and appearance over time, even under heavy vehicle traffic. The self-compacting nature of HPB also means that it effectively fills in voids and spaces between the pavers, reducing the risk of weed growth and insect infestation.

Ease of Installation

The self-compacting feature of HPB simplifies the installation process, reducing the need for heavy machinery and labor-intensive compaction. This not only speeds up the installation but also reduces the overall cost of laying your interlocked driveway.

Limestone Screening

While limestone screening has been a traditional choice for paving base materials, it lacks some of the key advantages offered by HPB. Limestone screenings can become compacted over time, which may lead to issues with drainage and potentially result in water pooling on your driveway. Additionally, the finer particles in limestone screenings can make the material more prone to shifting and settling, which can affect the longevity and appearance of your driveway.

The Verdict

Given its superior drainage, durability, and ease of installation, HPB emerges as the clear winner for your interlocked driveway project. It's an investment in the longevity and performance of your driveway, ensuring it remains stable, attractive, and functional for years to come. While limestone screenings may offer a cost-effective short-term solution, HPB provides long-term benefits that far outweigh the initial savings. Opting for HPB can save you time, money, and hassle in maintenance and repairs down the line, making it the preferred choice for a high-quality interlocked driveway

Step 5: Edge Restraints

Edge restraints are essential to prevent the pavers from shifting over time. These can be made from aluminum, plastic, or precast concrete or cement. They are installed along the perimeter of the driveway to lock the pavers in place.

Step 6: Laying the Interlock Stones

Once the base layer is prepared and perfectly level, you can begin laying them according to your chosen pattern. Leave a small gap between the pavers for joint sand, which locks them together and provides additional stability. Note that today it's not uncommon to have interlock or paver stone manufacturers already incorporate spacers around their stone.

Step 7: Compacting and Sealing

After all the interlock stones are laid, sweep joint sand into the gaps and compact the surface with a plate compactor. This process locks the pavers in place. Finally, consider sealing the interlock stones to protect against stains and enhance their color.  Nevertheless, there are many types of paver stones that today do not require sealing. In my next blog, I will discuss the different types of paver stones and interlocks you may choose for your project.  

Maintenance and Upkeep

Regular maintenance, including re-sanding the joints and sealing the interlocks every few years, if necessary, will keep your interlocked driveway looking great and functioning well for years to come.

By carefully planning and executing each step, using the appropriate materials, and ensuring proper drainage, you can create a durable and aesthetically pleasing interlocked driveway. This not only adds value to your property but also provides a functional and reliable surface for your daily use and for many years to come.