Doug Miller wrote:
In article , "CraigT" wrote:
All right, I've been convinced by you guys to open up the wall.

My prediction of what you will find: absolutely nothing wrong.

I still think the cause is what I said the first time: solvent exposure,
either in the form of overspray from staining the deck, or whatever was used
to clean up the overspray.

Before opening up the wall, at least look at the back side of the siding you
removed. If the problem *was* a heat source inside the wall, then the damage
on the back side should be at least as bad as the damage on the face. OTOH, if
there is no (or only slight) discoloration visible on the back side, that
would be the strongest possible indication that the source of the damage was
on the outside of the house -- with solvent exposure being IMO the most likely
culprit.

I gotta' go w/ PeteC on this mostly...the OP said the solvent/deck was
done in '06 and this damage didn't show up until within the last two
weeks -- that's pretty long incubation time for a solvent to act.

Definitely OP should find out what's going on inside the wall if only to
confirm conclusively it was all a surface damage on the outside...

If we're betting/guessing, I'm still on the side of somebody pushed the
still hot grill over there sometime...

--