Roof Decking from Attic SUBSTANCE

Hello ALL!

I was in an Attic and observed the following substance on the Roof Decking.

Please click the link below.

Thank-you everyone for your input!

Just-in-case, the picture link below does not open, let me try to explain in detail:

There is a white-like substance that looks
efflorescence-like with a faint pale green tones
on the under-side of the wood-deck. I normally would suspect MICROBIAL conditions, however, the area in question has some even areas; as if it was painted along straight with a brush.

Hope this description helps!

What link?

I was not able to upload the picture due to size.

I can e-mail you (or anyone for that matter) for advise.

Let me know and thank-you!