Designing Kitchens and Bathrooms - After removing mesh and concrete.

What a job, what a mess!! Finally removed it all.
Under the mesh and and concrete there was a black paper, tar paper? Which was attatched to green board.
My husband does not want to go all the way to the studs in the tub surround area and will leave the board and tar? paper up and then for the tub surround use cement board on top of it all.
My question is, do we still need to put a plastic vapour barrier under the cement board or is the black paper sufficient?
Thanks in advance.

The tarpaper should provide the moisture barrier needed for installation of the cement board. I would make sure of my measurements first to make sure a new tub will fit in the same distance. If not, I would remove everything back to the studs and start fresh with new vapor barrier and cement board underlayment.

You've already done the hard work. Taking down the greenboard and felt will be easy. This will give you the opportunity to see what kind of condition the studs, insulation and everything else is in. Also you dont need the greenboard there if you are gonna put up cement board. If you leave the greenboard, you'll need to use longer screws and the cement board will not be secured to the studs as well. After you remove the greenboard, if all is good, you can proceed by putting up new 15lb felt or 6 mil poly, then 1/2" cbu.

You've already done the hard work. Taking down the greenboard and felt will be easy. This will give you the opportunity to see what kind of condition the studs, insulation and everything else is in. Also you dont need the greenboard there if you are gonna put up cement board. If you leave the greenboard, you'll need to use longer screws and the cement board will not be secured to the studs as well. After you remove the greenboard, if all is good, you can proceed by putting up new 15lb felt or 6 mil poly, then 1/2" cbu.

Yes it was VERY hard work. The tiles, mesh and concrete, were up to the ceiling on all three tub surround walls, and half way up the rest of the bathroom walls. The wall of the tub with no plumbing we discovered, because of the thickness of the mesh and concrete was 2 inches away from the edge of the tub. So we basically had to add another 2x4 frame to the original studs AND fir that out with 1/4 inch plywood so that when the concrete board went up it would actually cover the edge of the bath.
And that was the reason behind wanting to leave the green board uo on the tub exterior wall and the interior wall (plumbed side) but just from the tub edge to the corner, because we would then have to also reframe or fir out those portions of the wall also, becuse of the thickness variation.
I tried to talk my husband into taking it down!!!! but he said it would be fine!!.
The problem I have in adding an extra layer of wall board on top of what is there is that are we not going to run into problems when we have to screw into studs that are already screwed into with the old wall board?
I would prefer to take the old stuff down, but is firing the studs out the right solution?

Greenboard will not be fine in a wet area. I know it is a pita, but in order for you to have a good retile effort, you will need to apply cbu on all the tub wall surfaces. Of course this would entail removing the remaining wall covering.

Larrys right. Take down the remaining greenboard.

The only area with green board left is the back exterior tub wall, both sides of the tub are down to the studs.
Because of the thickness issue, he wants to put tar paper over that green board and then cement board on top of that and of course the two sides. So all 3 sides will have CBU.
Would that be acceptable?
thanks