Three inches is a great thickness for a residential asphalt driveway that sees minimal to moderate traffic from cars, SUVs, and pickup trucks. However, a thicker driveway can better withstand the weight of a heavier vehicle, such as a trailer or a recreational vehicle. If you drive a heavy vehicle on a thin driveway, you risk cracking and damaging it.

While some areas may allow for a slope of up to 20%, this is often the maximum slope for driveways, with a few exceptions of up to 25%. Other regions may have a maximum of 12%, 15%, or 18%, so check with your local building department to ensure you’re laying a driveway that is up to code for your location.

To adhere pavers to concrete, you can use either mortar or a concrete-specific adhesive. For border pavers, a polyurethane-based adhesive is a good choice as it expands and contracts with temperature changes, keeping them firmly in place. For the non-border pavers, polymeric sand is used between the joints to prevent shifting. In most cases, it is also recommended to lay a permeable sand layer below the pavers to ensure proper stability and drainage. Before starting, always take the proper preparatory steps for a professional result.

The most common causes of sunken pavers are poor base preparation and insufficient compaction. The problem could also be how your pavers were installed. If the soil beneath your patio or walkway wasn't compacted, it will pull pavers down as it settles. Additionally, using bare soil instead of making a paver bed with compacted gravel and sand can cause sinking over time. To fix sunken pavers, consider recompacting the base and addressing any drainage or erosion issues in the area.