I'm siding a garage where cedar shakes were installed 1/2" above the slab and 2" above a gravel drainage bed. This lasted over 50 years I'd guess. The shakes, plywood backing, sole plate and several studs were toast. Water and carpenter ants!
Now it's level and sound waiting on lower siding to complete. I've been reading this thread and mulling over the the best way to finish this baby. I was thinking maybe bug/weather rated plywood under new shakes or cedar planks might work. Installed around an inch above slab.
I'd like to hide the plate but no way going to yank the skirt up 4 inches! The studs would show. If the plywood touched the slab, wouldn't it wick up water and swell? Stupid garage!
i too thought that the plywood would wick moisture and swell, but it seems not to. the code here says i HAVE to have anti-bug/wet plywood or 2x at least 6" from grade. so that's what i have. i just needed a good way to finish the bottom from the ground to the siding so it'd look nice. i mulled over faux brick, stone veneer, stucco, etc. but i like the coil best for ease of install.