My neighbor has this black soot outside his window. It can be cleaned off and reappear with in a couple days. House has a natural gas boiler in the basement. Curious as to what could cause this. And concerned about the indoor air quality.
And you can see it is heavy outside the center window and slightly over the corner window.
there is no range by that kitchen window.
TIA
Replies
Instead of soot collecting going up, any chance it’s something coming down from above?
Does this side face the main weather direction?
What would happen if they just washed off the bottom siding course?
What makes me think it is coming from inside is it’s heaviest by the header of the window then starts to fade and dissipate as it rises. And when it’s washed off and starts forming again is starts at the window header and rises up.
You can see it mildly at the front window header which remains
Closed. This kitchen window remains open a lot.