Preserved aircraft- surfaces they stand on

Many years ago I reached the obvious conclusion that displaying an aircraft outside was bad for it’s long-term health.
I also thought (based mainly on observations of the under-wing corrosion on an ex French AF F-100) that standing on a pervious (non-waterproof) surface was also detrimental to the well being of the aeroplane.

However it was just that – a ‘thought’ and, all these years later, I wonder if anyone has done any proper research on the subject?

ie are impervious surfaces (concrete, tarmac, etc.) better or worse than pervious (grass/soil, sand, gravel, etc.)?

Roger Smith