Worth it to build mezzanine levels in self storage facility?

[Peter Lee]

Anyone have experience with these small overhead units?  They are typically accessed by rolling step ladder.  One thing I hear is the major liability issue from ladders tipping or people falling carrying stuff into their unit but we do have a space which is 14'-6" high which is why we are considering building these out.  

Any thoughts appreciated on the risk involved and what people lease these units out per sf relative to the units below.