insulating/under pinning sub floor

[Mikelopic]

  breaking ground this spring! we are using your method of post and pier,thank you. First step,sub floor... we will be appox.2ft. plus off ground level
     can you please give us some tips on the best way to under pin sub floor to keep out the critters. insulation(2by8),I am worried about moisture,condensation etc. if we seal it up to tight. thank you, this site is very helpful!

[jraabe]

The method is best described in the Little House plans but in general fill the floor joists with insulation and put up something on the bottom of the joists to hold it in place, keep air out of the insulation but not be a vapor barrier. You can use Tyvek with lath slats or black poly with holes poked into it to let out vapor and then held up with stapled chicken wire or pegboard.

There are about 30 other ways.... If the insulation is allowed to sag it can break the air barrier and lose its R-value.

Also skirt the foundation with something to keep racoons, dogs, and insects from setting up housekeeping.