Hello,

I purchased an 85yo house in Philadelphia about 4 years ago.

Two issues, most likely related:

Issue #1:

I've noticed in the past couple of years that regardless of day/night/season, that one of my exterior walls always looked damp (even after weeks of no rain and 90*+ weather, which should've dried it out, one would think). Thinking that maybe the cement on top of the brick was retaining water after rains, I put a clear sealant on the concrete. The sealant works well (ie: when you hose the wall, or it rains, water runs off wall like water runs off a Rain-X-treated window).

Having said that, the exterior wall now seems to remain damp all the time, which leads me to believe that maybe groundwater was the real culprit, and now that the exterior wall is sealed up about 2 feet off the ground, that the water is now creeping up the wall.

Thoughts?

Issue #2:

I've also noticed on the landing at the top of the stairs that lead down to my basement, that the concrete will sometimes get like little powdery pimples, that either disintegrate into dust on their own (like cigar ash that falls under its own weight), or, once touched, turn into dust.

Also, inside my house, on interior wall that backs up on the aforementioned exterior wall, I'm starting to get blisters and/or air pockets under the paint (some of which "crunch" like crispy Saltine crackers when you press on them, and texturally, through the paint, feel like sand, which makes me think the concrete / mortar that was used to originally bind the bricks, when the house was built, is now disintegrating due to the moisture that seems to be trapped in the wall).

I'm thinking that the same moisture that I can visually see on the exterior wall is the reason behind this interior wall phenomenon as well.

I've attached multiple pictures of both the exterior, landing and interior walls (unfortunately, I scraped off all of the powdery eruptions from the landing walls before thinking to take pictures).

Having said all of this, can someone confirm/deny the reason behind this happening, and more importantly, how can I rectify the situation so that this doesn't keep happening / get worse?

Thanks,

P.

P.S. I also have a video of the interior wall, and me touching various sections of it and the resistance, or lack thereof, it gives me...if anybody would like to see that to make an assessment).