Just put up some new exterior corner trim, 3 1/2" wide. I don't know if the building paper in intact or how it was installed way back in '47. I'm thinking I might not caulk but I'm not sure.
I would, using paintable caulk. And then paint---because the caulk may mold/mildew otherwise.
Thanks, Handymac - will do as you say. Thinking about it some more, that's the way to go.
What function will the caulk perform?
I was thinking the caulk would keep water from entering the house at the corners where the siding boards come together. I read that a on a properly wrapped house, the wrap would serve this purpose and caulk would only serve to keep water in, which I suppose assumes water WILL inevitably get in due to poor maintenance. I'm pretty sure that the building paper on my old house isn't functioning that well, so caulking might be a good idea, as long as I keep it maintained and painted.
BTW, all the boards at issue, siding and trim, have been primed and painted, including all end cuts, if that makes any difference.
I would not caulk that. There is 3 1/2" of coverage before water could enter to framing. So IOW there is zero risk of water entering and damaging the house. However, if caulked, you have created a perfect 3 1/2" water trap for any that did enter.
The risk outweighs the reward.
OK, sombreuil, that makes sense too. (I've just started learning some French and that word is a pronunciation challenge.) Once caulked, it's done, so I'll not caulk and pull up some trim this winter to check how it's going. The old trim wasn't caulked but for one corner and when I tore it all off, the caulked corner seemed a bit moist and this is months since the last rain. Admittedly, I hadn't properly maintained the caulk.
"when I tore it all off, the caulked corner seemed a bit moist and this is months since the last rain." This pretty much demonstrates what sombreuilm was saying.
I agree that no caulk is the best approach.
To clarify, what the no-caulk camp is saying is that it's impossible to keep water out of this joint, even if it's maintained yearly? Or is the suggestion not to caulk based on the assumption the joint will NOT be maintained. Or maybe the moisture behind the trim is coming from inside the house? Additional varibles, I suppose, would include climate, insulation and condition of building wrap. A corner would be just wood, no insulation, so I'm not sure how that would effect moisture buildup from inside the house. Just curious as I'm now convinced not to caulk.
All caulk will do is trap water longer letting rot start sooner.
Leave it alone