Here the home was built (1974) with a concrete slab about 2 inches below the wood siding. Then the addition of cemented flagstone brought the clearance down to zero in many spots.
Now the question has arisen: are there any exceptions to the 8-inch-above-grade rule, such as installation of a vapor barrier, or if there were some type of drains or drainage canal installed around the edge of the building?
Step one: Begin by explaining why the rule that you stated exists.
For moisture/rot, flooding, and to a lesser extent termites, right? We are in Hawaii, so snow is not a problem.
Welcome to our forum, Alexander!..enjoy participating.
P.S. That will rot with the mortar u on the wood siding.
Any cementatious material like that should not be in direct contact with wood siding as it will hold moisture, leading to wood rot. Some form of moisture barrier or flashing should have been used.
This might give you a better understanding of the reason for the 6-8" exposure below siding.
The minimum distance between siding and grade - Is Your Siding Too Close To Ground?.
Just saw something like this yesterday. That may not be hardiplank exactly but it looks like fiber cement. Here’s a snip from the James Hardi instructions for installation over flat surfaces. You need 1-2”, it looks like. (Why don’t thy just say 2”?! Is it 1” or is it 2”? A minimum shouldn’t be a range of numbers, IMO)