On one of our dining room walls we have a perfect storm of variables, and not surprisingly we have extensive water damage on that wall. When we moved in, there was a 4 inch up/down plaster crack on the wall with crumbling powdery plaster coming out of it. Since it didn't appear to be getting worse and we were newbie homeowners, we just put a chair in front of it and called it a day.
Fast forward six years and I decide it is time to fix it. I watch countless plaster repair videos and decided to tackle it myself. This also corresponded to when we were painting the dining room. When I was cleaning out the damaged plaster, I realized that the original cast iron stack was running right behind the crack. Eureka! But since this is a very costly fix that basically means gutting the floor of the original bathroom upstairs, we've decided to make that a four year project if we can make it that long.
I was pretty pleased with the plaster repair results, but not surprisingly within three or so months, the new plaster was already getting moist again and producing this kind of efflorescence on the surface of the paint. In addition, there are multiple other places now where the paint is bubbling under the window sill and up further on the wall away from the stack and the window.
Needless to say, we are flummoxed. I'm guessing that the original damage is from the cast iron stack that is slowly releasing water, but it didn't feel wet to the touch when I uncovered it. But what is causing the other damage on the wall? Is it faulty mortar joints?
Here's the perfect storm of variables on that wall:
Original plumbing running through the plaster on brick.
chimney on that side (but up two stories)
directly above the return vent for the whole house
air conditioning directly outside with a furnace exhaust and a pipe that pumps out cold water
I wanted to solicit experiences from those of you who have dealt with this type of water damage. In your experience, what are the likely culprits? And with damage this extensive and random, do you think we need to have the entire wall re-tuckpointed? Can water travel that far down from the chimney? There's no damage above it on the second floor.
Any feedback or guidance would be much appreciated.