Get matched with top paving pros in Somerville, TN

Asphalt and tarmac are not the same thing. Traditional tarmac, short for tarmacadam, uses tar as a binder to hold crushed stone together. Asphalt uses bitumen—a byproduct of crude oil—to bind aggregate. Though tarmac was once a go-to for roads, asphalt has become the modern standard. And these days, most surfaces referred to as “tarmac” are actually asphalt. So, while the names may overlap, the key distinction lies in the binder—tar for tarmac and bitumen for asphalt.

Professional installers often include a deep layer of crushed gravel under permeable pavers to allow more runoff to soak through into the soil below. Many installations will include multiple layers of gravel, with coarser aggregate at the base and finer aggregate that sits on top of that bottom layer. Above the gravel, you’ll often find coarse sand that helps reduce paver shifting over time. Some permeable paver designs include a water collection system set into the gravel layer to route runoff to a safe area for disposal.

The stones do not work well on uneven ground. If the stones are not buried into the ground and made level upon installation, they almost certainly will shift or crack on uneven ground. Additionally, rainwater or water from sprinklers can run under the edge of an uneven paver, causing erosion. In a freeze and thaw cycle, trapped water under the paver can cause the problem to worsen by shifting the stepping stones around. Use a bubble level to make sure the ground under each paver is as even as possible, even if the nearby ground is uneven.

Interlocking pavers offer a number of advantages over regular pavers. For instance, they’re more durable, more resistant to shifting, and easier to repair. There are also permeable options that allow for drainage. However, interlocking pavers are more often more expensive than regular pavers and are prone to growing weeds over time.