Mold or rust stain on roof truss

Question

Paid a visit to my attic earlier today to see if there was any winter damage. Looking all good except for a small piece of truss that has a black stain on it (see picture). I would have said mold but the symmetry of the stain is odd. Could this be a rust stain or something else that was already present when roof was built? If you look at roof sheathing nearby and cardboard piece preventing blow-in insulation from reaching soffit, it does not look like there was water infiltration anywhere nearby.

Looking for any input that you guys may provide.

I meant..leaks due to damaged shingles or ice dams. Maybe even condensation cause by roof vents blocked by heavy snow. Winters in Canada get nasty. — dstmartin, Apr 29 '21 at 15:36
I think that is paint on the lumber, but if is that corrugated cardboard under it in the photo, I would get rid of that, as it can mold. Hard to tell phone the photo exactly what it is and why it appears to be stapled to the lumber, — RockPaperLz- Mask it or Casket, Apr 30 '21 at 01:41
(How in the world did I type "phone" when I meant "from" in the above comment? Mods, feel free to correct my comment!) — RockPaperLz- Mask it or Casket, Apr 30 '21 at 06:42

isherwood · Accepted Answer · 2021-04-29T15:03:21.950

23

Neither. It's labeling paint. It was either sprayed onto the entire lumber unit or this truss set for identification.

_source

edited Apr 29 '21 at 15:03

answered Apr 29 '21 at 14:58

isherwood

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Are the dark marks on the ends of a few of those pieces of lumber burn marks from the rotary saw? – RockPaperLz- Mask it or Casket Apr 30 '21 at 06:44
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Or potentially, before being installed in the roof, that piece of wood was used to hold up something else that was being spray painted, and you're just looking at some over-spray. Either way it's perfectly harmless. – Darrel Hoffman Apr 30 '21 at 13:49
@RockPaperLz-MaskitorCasket it's mostly natural variation in the wood. – isherwood May 02 '21 at 00:54
@isherwood Thank you. I was wondering why I rarely see it in wood I cut. Probably just different species or variation of trees. – RockPaperLz- Mask it or Casket May 02 '21 at 01:09

Mold or rust stain on roof truss

1 Answers1