Tim, look a bit more closely at the picture.

In the white area, you can see that the white is in fact 3 dimensional. There are sections where it stands off in balls, like white mold will, and then a thin fuzz is spread out otherwise. The pattern of the balls and ridges is that of mold.

Also look closely at the darkened area. I thought too it was just blue stain, but looking closer at it it seems to be mildew instead. I say that for 2 reasons. 1: the color: it seems to be a deep brown-black, with little blue in it (take that for what it's worth, I know that color is affected by the picture and by my monitor's settings) 2: There are 'spots', many black circles, in the affected area, which is how mildew colonizes.

If you look elsewhere on the timber, there is certainly blue stain in this timber. So I could be wrong here. But to me it looks more like mildew...

If it were a condensations issue, not a water flow issue, I would expect to see the drywall in good shape. The water will collect on the coldest things present, which is going to be the wood, and it may not even be collecting in high enough quantities to be detectable to the casual observer, just enough to keep the wood damp would cause what I am describing, yet have no effect on the drywall.

To be clear though, I am not asserting that this must be the case here, I am just saying it is possible, and telling why. Like I said earlier there is no way I or anyone else can ever come up with an accurate scenario based on a picture, we would have to be able to see it to know for sure. All we can do is give you the information you need to be able to figure it out.

DLB

[quote=RichardR]I think I just attached a picture of the damage, looking up at the beam where it meets the knee brace, with PP damage excavated as much as possible.

Here in Richard's words he says the damaged area was excavated as much as possible. I suspect that it was excavated by a person, revealing the bug tracks/tunnels. Then painted with some solution. I also suspect if we had a bigger picture of the frame we would see more "blue" stain through out the frame.

I could also be mistaken, as well. I have used plenty of pine in various stages of "rot" reclaimed, if you will. It is even present on the cover of the latest issue of Timber Framing. There may even be a spot of ambrosia beetle present on the cover, in the wane on the top plate.

Tim, I suppose only the owner can tell us the case. I'd like to see some pictures of a larger area of the frame.

I don't generally like to see blue stain to that degree on an exposed face of a timber, and suspect few would.

Part of my reason for suspecting a rot issue is that it is unusual for ants or similar bugs to invade dry wood, they tend to go for weak spots, and in my experience they favor fungus-compromised wood.

Another possibility though is that there was some kind of beetle egg present in the sapwood before the frame was ever raised, and a lone larva ate its way to maturity. This of course would require the affected area to be sapwood.

Looking at the picture, I think you might be right about the white being paint, and the balling could just be a result of the paint mixing with the insect dust.

Thanks for all of your interest. some replies and clarification:

There is no white paint, or mold, on the beam in the photo. the bright white area is simply the exposed surface of the pine, where I excavated as much as I could. It may look odd because of the glare from the flash.

the beam is supporting a SIP roof, and an OSB-sheetrock panel wall. it does have bluestain, which was present when I raised it 5 years ago. I would bet a year's salary there is no moisture coming in from the outside the beam now.

I haven't isolated any insects. There have been no ants visible anywhere near here, and I am familiar (way too familiar!) with carpenter ant damage, and this isn't it. The frass is a very fine powder, which is why I thought PPB. The damage is active--I did the excavation because we saw new frass piles on the floor below the beam.

I think it's likely the insect was present at raising, though I cannot swear to it. my concern is about both the structural integrity of this beam, and the possibility of spread to adjacent ones.

any good advice on cutting the beam out? Perhaps I should start a separate thread on that.

thanks, Richard

I think, then, that it is a beetle larva that was present in egg form when the log was milled. Can you tell us whether or not the infected area is or is adjacent to sapwood? If so, that would support this theory.

If this is the case, then they are sapwood-eating beetles that will not continue to infest the wood. I see these things a lot in dead standing trees.

Bugger, could we have a better picture? If it is so bad the timber needs replacing a new picture would be nice before that happens.

I know if I leave boards, flitch, with live edges in piles there is a worm which gets in under the bark and will subside for a number of years. I believe in the cambium layer just under the bark. They will move around some. They are a different bug than the pine borer which will work its way through the log. They are smaller in size and leave a very fine power. Or they could be a stunted borer. How big are the bug channels?

Was there bark left on any of the timber? They could have migrated and came out there by the brace?

Keep an eye out for more frass.

If you look at old timber, usually in the cellar, you will find bug tracks on the wane, well some of them.