Not sure if oil soot or coal soot, but it was capped off just below the oil burner flue with about 6 inches of concrete, I'm guessing so it couldn't be fuel for a fire. Easier than trying to remove it ? Found a permit for a 275 gallon oil tank storage for a fireball boiler installed 1963 and another permit for L.P. tanks for a Coleman furnace, water heater and cook stove issued 1951 I remember a floor furnace when the house had no hydronic radiators so this must have been it: WWW file from 1944 I always thought it was coal, but gas makes more sense. Part of a chimney demolition/removal in my kitchen. Found a flue/hole on the living room side of the chimney that was unexpected. Capped with a paint can lid and some kind of hard as rock plaster-type goop. No wall thimble. Likely a new wall. There was a flue access on the kitchen side with a wall thimble which I expected to find as I remember a big huge stove in the middle of the kitchen when I was a kid with a big exhaust on the back going into the wall.
Interesting. If there was no cleanout below at the floor level, it would be pretty difficult to clean. I've heard of a story from a gas utility guy of junk built up blocking a gas boiler exhaust in a chimney that he red tagged. If the chimney was not capped for years, it could have been a build up of broken mortar, old dead birds, leaves, etc. I've seen covered holes from old coal stoves in bedrooms. What age is the home?
There was a cemented shut clean out at the bottom. Half round, no hardware ( no door or anything ) about 8 inches wide. Didn't know it was there until a pried the last bits of busted block out of the floor. The property was purchased in 1904 by my great grandfather. At that time there was a single room summer house and another building to escape the heat of the city. This is the "other building" . Supposedly build 1928 but I think those Town records are based on full time occupancy and doesn't actually reflect when the house was built. Supposedly built of old railroad box cars but I haven't taken enough walls apart to find evidence. The bottom 2/3 of the basement walls are just stacked stones with mortar. It's old. But not historic.
Neat history. Same vintage here. Fieldstone with some early concrete block on top of it. Lots of coal clinkers around the foundation and under walkways here. Opening walls can be very interesting in old homes.
