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.

enter image description here

  • what is winter damage? – DMoore Apr 29 at 15:29
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    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 at 15:36
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    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 at 1:41
  • (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 at 6:42

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

enter image description here source

  • 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 at 6:44
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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 at 13:49
  • @RockPaperLz-MaskitorCasket it's mostly natural variation in the wood. – isherwood May 2 at 0:54
  • @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 2 at 1:09

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