Repair of vapor barier from inside behind stucco

[chotamota]

I have had a slight water leak show up on the dry wall under a big window. On cutting out the dry wall and removing the insulation I see the tarpaper behind the stucco is falling apart into pieces. I have removed the crumbling tarpaper and the stucco is now exposed clear with the steel wires. This is a small area approximately one foot by six foot with studs in-between. What is the best way to replace the tar paper before I put the insulation and the dry wall back?
Please help.

[pushkins]

Chances are the damaged drywall didn't result from the failing tar paper, most often the water comes from higher up than where you physically see damage, look for areas around the perimeter of the window for anywhere water can permeate, like cracked caulking etc...
To replace the paper cut a length longer and wider than you need, feed it in between the studs and stucco try to tuck it up under any paper above it so the higher paper overlaps the lower. At some place probably the upper corners your going to need to fold in a small tab of tar paper to nail to a stud to hold up the paper.
Make sure the tar paper goes as far down as you can get it.

[chotamota]

Thanks a lot for such a prompt response. The outside stucco and cracks around the frame of the window have already been repaired and caulked well to prevent any leakage of water in the future, I hope.
I want to make sure we do something to replace the crumbled tarpaper before we close the dry wall up. You suggestions are wonderful. I do not see any space between the studs and the stucco where tarpaper can be tucked in. The openings we have made are at the baseboard level and there is the base of the frame bolted to the slab of the house. On the upper side is the window but we cut the dry wall about ten inches below the windowsill. I can push up the tarpaper as far up as it can go and glue it to the exposed stucco with vertical strips of glue. I am planning to overlap the cut tar paper on the rest of the three sides to fold it on the inside frame of the studs for each section and after stapling it well to the wood seal the edges of the paper with caulking before putting insulation and capping it with new rock board dry wall to close the opening.
I will try to put the tarpaper in each opening between the studs so that it is sealed properly all around from inside to stop any water droplets from flowing inside to the dry wall.
Do you think this will work?