I had a customer in Baltimore (circa 1993) who began to think her newly purchased 18th century row house in Fells Point was possessed because every time it would rain these huge water blisters would occur underneath the paint along with a foul odor. She had called on plumbers, roofers and several handymen to no avail. The customer who was Chinese had some serious superstition beliefs and was literally at the point where she hired me to fix the paint just to jazz the place up enough to sell. I mentioned I had tons of experience with old homes and offered to inspect the home first. I had to convince her this was a common occurrence in older homes.
I convinced the client to let me start on the 3rd story roof which required climbing on a 40 foot ladder and then carrying a 24 foot ladder to the top to inspect the most obvious place first, the chimney. As suspected there were multiple areas missing mortar at the top of the chimney. Along the dormer roof line and above windows, there were openings for water intrusion which is not uncommon for very old homes. But this home had a new roof and paint work completed prior to purchase so what gives?
I researched and called on some of the older contractors in town to find out how to match the mortar. I resurfaced the top and pointed up the body, added flashing to the roof line and sealed above windows with oil-based caulk, then color matched both the roof and brick to blend the flashing.
I then went inside confident the repairs fixed the issue, scraped and removed the soft and moldy plaster, allowed it to dry out. When I called after the next rain, the customer was ecstatic, (no more leaks!) when I returned Lesli Li was sitting there with her mother and they both heaped praise on me. I finished the project by oil priming the eroded area’s used plaster of Paris for repairs and top coated over the old oil-based with oil paint. I gained multiple clients in the Historic areas of Baltimore after that, and this was all pre the yelps and google!