Insulation, Radiant and Vapor Barriers - Strange insulating job

Your turn to help me out.

My 4ft deep crawlspace (all dirt) is insulated in the following way:
2X8 Floor joists are insulated with 4" R-19 faced(placed upside/vapor barrier down) and un-faced batts. This is then covered with 1" styrofoam sheets.
This home is brick and crawlspace area is 2100sqft.

Questions,
1) Should I pull all and start over correctly?

OR

2) Can the un-faced and styrofoam sheets be left as is. The faced will be removed and replaced or turned over (barrier up).

3) Presently there is not a vapor barrier on the floor of the crawlspace. What mil plastic barrier should be used?

4) Is R-19 sufficent for floor insulation? More? Less?

Thanks in advance for your help.

Hello majakdragon, here's my humble opinion. If the insul. is in good condition,

I would be inclined to save it and strip off the vapor barrier, as well as the

foamboard. ( I wonder how they managed to get 4 by 8's of anything into

a crawlspace. I wonder if they stored them under the joists before the

decking went on ) In any case, if you were starting from scratch, you

couldn't do much more than the 4in. insul. you already have, at least in my

mind, not enough more to make it worthwhile to do a complete redo. When

you consider that a house with 2 by 6 flr. joists certainly wouldn't have

more than 2 by 4 walls ( R-11 or R-13 ), more heat would be lost through

the walls than through the floors. So maybe it wouldn't be a real good use

of your time and resources to put more insul. in the floors than into the walls.

Only 4 mil poly is required around here for vapor barrier on the ground. I like

6 mil better because it's easier to work with, easier to tape the overlaps. I

use the same tape you use for tyveck and silicone caulk the edges to the

foundation walls. Four foot deep crawlspaces, in my experience, don't

have much trouble with moisture problems, but it's probably better to use the

VB than not. I find that a fine chicken wire under the joists does a good job

holding up the insul. The foamboard wouldn't meet fire-codes in most areas

of the country, unless it had 1/2 in. drywall over it. Not very practical in a

crawlspace, although I once saw a crawlspace with the usual foamboard on

the foundation walls and some inspector made them put drywall over the

foam. By the time I saw it, it looked like an incubator for mold with all the

rotted drywall. Sometimes they get a little carried away. Good luck with

your project, my back aches just thinking about it.

This is the way the house and crawlspace are set up.

The crawlspace is concrete block wall+2" air space+ brick

Floor joists are ACTUAL 2X8 rough hewn lumber (lots of cedar and cypress saw mills here)

Brick goes from ground to roof.

Styrofoam sheets are 2' X 8" X1"

Exterior walls are 2 X 6 rough hewn lumber(see above)

I read your dilema.Its funny that I have the same situation except my home is log.The crawl space has the vapor barrier facing downward. Everything I have read so far confirms what I have known for years, paper facing the living space.My foam board is the 4x8 foil faced. I am thinking of just turning the fiberglass around and using a new type of foil encapsulated poly barrier.It has a fire rating. I have a question in the forum if anyone else has used this type before.