Treated lumber?

[Eagle74]

The mesh size as I referred to it is the sieve mesh size (sand granule size).

 

Stainless steel mesh is used in place of metal flashing for termite shielding or laid around the foundation to protect openings in foundations though. It wouldn't really help for the project noted above unless laid under and then up around the sides a bit. The mesh is fine enough that termites can't pass through it and tough enough that they can't chew through it.