How many concrete piers do I need to support a tiny house (12x28 and 20feet high)
Given the size of the piers and their anchor depth and the fact that you can use metal (ibeam) cross beams, you can definitely do just 4.    Remember when building on piers, more is not better (unless we are talking large commercial building).   When you add more piers you are allowing for a greater future issues with leveling based on heave.
Now that was just the &quot;minimum&quot;.
In real world home building you would probably have three piers on the long side - so 6.