What is that ? Is it a big deal?

I’ve seen this before. It looks really scary. I was in a room with a cathedral ceiling. I could see distinct grey shadows along ceiling that seemed to follow the line of all the roof rafters.

What’s that? Is it mold? Is water going through the rafters and staining the ceiling plaster? Saw one last week with a ceiling like this; my clients have an accepted offer there. Until I get to see a place  with a home inspector, the question lingers.

So, I got the chance to ask Kevin Morrison. Now I know the answer. Do you?

What is that?