Deckman, you have answered this question in the past but not directly as it relates to my project. I live in the Charlotte, NC, area where we don't typically get snow but temperatures can get below freezing. I am getting ready to start building a 10x10 shed and I would like to keep the finished height of the floor at about 8" or so above grade from a convenience and aesthetic perspective. This will require me to excavate for each pier which I am prepared to do. The plan is to backfill with gravel. However, I am wondering about frost heave in my area and wanted to hear your general recommendations / thoughts about my proposed foundation plan.

Thanks!
Steve Yudin
Huntersville, NC

Anytime you receive freezing temperatures, you can experience frost heave. In Charlotte, the risk is very low of effecting the block/floor/shed. Unfortunately, I can't say it couldn't ever occur.

In Charlotte, the biggest issue I see it the 8 inches. With 5 1/2 support and and 3/4 decking this is 6 1/4 inches of framing. This leaves 1 3/4 inch separation from the floor to the ground. Not a lot of air movement. You have a fairly humid climate. You may consider raising the floor another inch or 2 higher.