Blow in insulation service

[def90]

You can do blown in underneath.. What they will do is staple a mesh/fabric to the bottom of the joists and then fill'er up. See it all the time.

If the space underneath is dirt/gravel spray foam will act a bit as a vapor barrier as well.

Blown in pros: can service anything buried in the insulation without too much trouble vs spray foam where your plumbing and everything else will be incapsulated in the foam.