Torn bldg paper on stucco rehab

[Yikes]

My client is doing a "refresh" on an old (1970s era) apartment building. With some window replacement and larger PTAC units, we are needing to chip away old stucco around these openings. In doing so, we are finding the building paper is somewhat brittle. This is in a relatively dry region, and there has not been evidence of mold or rot underneath.
Of course the big question is whether all the building paper has become brittle underneath all exterior walls on the project. The low budget is compelling the owner to take a "don't look under that rock" approach, especially such information would compel us to strip all exterior skin and rebuild.

The contractor is asking me if elastomeric paint can substitute for bad building paper. My response is:
1. No, there is no code substitute for replacement-in-kind of building paper. IEBC allows in-kind repair. The elastomeric could be helpful for preventing rainwater infiltration, but it also keeps the wall from breathing.
2. As long as you can slip new paper or moistop underneath the old, the inspector cannot compel you to tear away more stucco "just in case the old paper we can't see yet has turned brittle behind the stucco".

Does that sound correct to you?

 

[ICE]

Would brittle paper be a problem if it isn't disturbed. I ask that the interface between old paper and new provide a 2" overlap of intact lath paper at horizontal laps and 6" at vertical laps. The lath paper may be somewhat brittle or extremely brittle. In the case of a little brittle they can achieve the intact paper lap. With a lot brittle they may have to remove a lot of stucco. Removing the plaster without ruining the paper is darn near impossible if the paper is dry and brittle. The thing is, I don't condemn the paper for being brittle....they do.

 

[RLGA]

I would recommend using a self-adhesive flexible flashing, such as as GCP Applied Technologies Vycor V40.