Originally Posted By: rmeyers
This post was automatically imported from our archived forum.
Long shot - but anything is possible! Probably would have had to been there to see it, but did any of the tradesmen involved in the roofing or flue installation use red chalk to mark their cuts or lines. Were there any brighter red areas under protected edges not subject to weathering.
I can show you a 4 year old shake roof where the carpenters did a cut out for a masonry chimney using a red chalk line and left red chalk dust residue on the nearby shakes that is still there today.
Blue chalk fades to white and white seems to fade out but the red will hang around for years!
Tip of the day from an old framing carpenter - Don't use red chalk!
If the flue was installed after the roofers had finished, I could easily envision the sheet metal men using whatever nails they had on the truck in support of Nick's theory of steel nails used on the flashings.
Also study the shape and pattern of the stain in relation to how water flows around the area for clues. If low grade tars or improper sealants were used around the flashings, they can sometimes "bleed out" onto adjacent surfaces.
When it's not OBVIOUS then it become INTERESTING!!! ![icon_confused.gif](upload://qv5zppiN69qCk2Y6JzaFYhrff8S.gif)