The paving stone installation process will vary depending on the geographic area you’re installing in, the native soil conditions, how much rainfall the area usually gets and the type of use the paving stones will expect to get.
A paving stone installation in southern California will not follow the same installation process as a paving stone installation in northern California. In northern California, the rainfall is much more than in southern California which will require a deeper sub-base preparation. In southern California the standard sub-base preparation for a typical residential driveway paving stone installation is 4 inches. Usually a geo-grid fabric is not required since the native soils are generally hard with minimal clay. In northern California, where it rain’s much more, a typical driveway paving stone installation will require 6 to 8 inches of sub-base preparation.
The differences in the preparation are simply because of the amount of rainfall and native soil type. Some areas in southern California have high clay contents in the native soils, which expand and retract when it gets wet and then dies. This causes swelling and instability beneath the paving stones. In these scenarios, it is important to excavate deeper and install more road base. It is also recommended to install a geo-textile fabric over the native soil, before laying the road base down. This will prevent the road base from getting mixed into softened clay when it saturated, reducing the potential of a sagging paving stone installation.
After completing your excavation and any required structural amendments, road base (typically a mixture of ¾” – gravel and dirt) is ready to be laid and graded for drainage. The road base should be compacted in 2 inches lifts until you reach your finish base grade. This will be either 3.5 or 4.5 inches below the final grade of the pavers, depending on the paving stone thickness.
After base is graded and compacted, you are ready to install your sand. Many companies use different types of sand. ICPI recommends using a washed masonry or plaster sand. This is more expensive, however, it compacts well and is strong. Once this sand is spread evenly, about an inch in thickness, over your compacted base, you are ready to snap lines and install your paving stones.
It is important to find your squaring point before you start. Know where you want the joint lines of your paving stones to line up with. Once this is found, snap chalk lines and lay your paving stones.
One of the final installation steps is to install an edge restraint. This will hold your paving stone border in place and act as the picture frame that holds your pave stones together. Again, many different companies use different types of edge restraints. There are plastic or metal edger’s that you can abut up to the edge of the paving stones and stake into the ground with 9 – 12 inch nails or stakes. I do not recommend these. What I’ve found to be a solid edge restraint is to trench along the field stones the entire depth of the sub-base, including the sand. If you installed 4 inches of base and 1 inch of sand, you would trench a total of 5 inches adjacent to the field paving stones. Mix some concrete and fill the trench ½ full. Then install a piece of #3 rebar horizontally in the trench and fill in the rest of the trench with concrete. Lay your border stones into the wet concrete, tamp with a rubber mallet and allow it to set. The concrete edge restraint will hold your border stones down and will also act as a retaining wall for the sub-base material so it does not mix laterally with any native soils.
The final step in the paving stone installation process is to install joint sand. This is done by spreading a ½” layer of angular, course sand over the paving stones. Use a vibrating compactor to vibrate the sand into the joints of the paving stones. This will take several passes with the plate compactor.
Next, you may sweep excess sand, spray down your new paving stones and enjoy!