* PIT ~ The pit should be deep enough to allow for drainage and ease of cleaning. Silt build up will occur over time. * FOOTING ~ A firm footing is required for both in ground and above ground installations. Depending on ground conditions, a compacted base is generally more than satisfactory, however if in doubt, a concrete footing should be installed. * GRID ~ Care should be taken to ensure that the grid sits correctly in relation to the camber of the road. * FILL ~ Compaction of filled areas is critical to successful grid installation and ultimately, grid life. * SURFACE ~ Ensure that the compacted ground surface is level with the grid rails. Incorrect surface levels will affect the life of the grid.