A paver base is made up of three levels: subgrade, subbase, and base. Each layer serves as a specific type of support and has a unique material composition. The lowest level of compacted dirt beneath the installation site is known as a subgrade. The middle support layer that sits on the subgrade soil is referred to as the "sub-base". On top of a base are the priciest pavers. Select th... https://modutile.com/product/permeable-plastic-pavers-24x24/