Our paving stone bases start at 6” (15cms) in depth for foot traffic areas, and at least 12” (30cms) for vehicular traffic areas.
We generally use what is known as a “clear or clean” base which means that we use an aggregate that is angular in shape, and has little to no fines in it, generally crushed granite.
The biggest advantage to a clean base is that the water will drain though it to the subsoil, and not sit in the fines of the base.
This is especially important in our freeze/thaw climate where frost heaves are the norm.
Under our base we use a 5oz fabric to keep our base material separate from the native subsoil.
We compact our base in lifts according to the rating of the compactor that we are using.
Once the pavers, slabs or flagstone is installed, we use the best type of edging suited to the individual project to keep the pavers in place, and we will either sweep into the joints a polymeric sand, or if flagstone with larger joints, we have the options of using rock or soil and seed between the joints.