Correct procedure for flagstone installation
For example, if we were to install an interlock project for pedestrian traffic only onto a clay foundation, the steps are as follows:
- The area is first marked out and then excavated approximately 11 inches.
- Approximately 7 inches of ¾ inch crushed limestone base material is installed into the excavated area, compacting every 2 inches to ensure stability.
- Then approximately 1 - 1½ inches of fine crushed limestone (screening) or sand is installed as a levelling base.
- The interlock stone is installed onto the levelling base once the grade has been set (always ensuring to slope away from the house approximately 1/8 inch slope to every 1 linear foot).
- After all the stone is installed and all the cuts are made, an edging system is installed around the perimeter of the project to prevent the stone from pushing outwards.
- The new interlock area is compacted to level and stabilize the stone.
- Finally, polymeric sand is swept into the stone joints to prevent weeds and insects. The area is lightly hosed to harden the sand.
Note: It is very important to excavate to the correct depth and compact the base every 2 inches in order to ensure no sinkage.