rough sawn lumber & rot?

[eggman]

I worry too much.. Here's some background. I had to put a new roof system on my 12x24 camp with a 12/12 roof. Wanting to be "green" I used all local RW lumber. It's got 2x6 rafters 1/2 x 6 sheathing. There's tar paper and black steel roofing on top of that and it's south facing so the roof get's hot for sure.

Currently it's a cold roof with fully vented soffets and ridge vent. But yesterday I preped it for 4in of closed cell spray foam to make it a "hot" roof. I did this by making tar paper blockers in every ridge and eave hole.

It's in very wet area in the white mountains of New Hampshire and moisture has been coming and going in the camp for a year now. The RW a bit multi colored

The worry. When I was putting the paper up at the peak, I swear I saw something that looked like dry rot on the very tip of a (one) rafter. It's wasn't white or moldy. I just looked as if mini bugs had eaten a piece of the tip. But I doubt it's bugs. More likely to be fungi.

So the foam is going in three weeks from now and I'm thinking (bad things). Should I rip all of the tar paper back off the peak before it's too late and spray the wood that will not be foamed (rafter peaks) with borate? Or since I am making it a hot roof, will the moisture be minimal?

[Don_P]

First off, there is no such thing as dry rot.  There can be rot which has dried. The wood has to have free moisture within the cell to rot. That level cannot be reached within the wood by humidity. So if it's rot it is either old rot or you have a moisture problem.

Are you certain it is not powderpost beetles...holes that a ball point pen ball will just barely not enter, fine frass on the floor?

If it's rot, find the moisture source, condensation, a leak...
If it's powderpost, heat or borate, borates will halt fungi but if there is a leak it will only buy you a reprieve.
Borates are not fancy perfume, it takes multiple wet on wet saturations to build a level within the wood high enough to disrupt their tummies.

Pictures?

[eggman]

First off, there is no such thing as dry rot.  There can be rot which has dried. The wood has to have free moisture within the cell to rot. That level cannot be reached within the wood by humidity. So if it's rot it is either old rot or you have a moisture problem.

Are you certain it is not powderpost beetles...holes that a ball point pen ball will just barely not enter, fine frass on the floor?

If it's rot, find the moisture source, condensation, a leak...
If it's powderpost, heat or borate, borates will halt fungi but if there is a leak it will only buy you a reprieve.
Borates are not fancy perfume, it takes multiple wet on wet saturations to build a level within the wood high enough to disrupt their tummies.

Pictures?

Might be beetles. Can't tell if there is fine frass because the place is a bit of a mess.

There is no leak, that I know. It's a new roof and I've been in downpours with it.

I've been using boates on my sill beams for a while with much luck.

For this problem, I think I'm going to take an easy way out. Before the spray foam is applied, I think I'm going to paint the areas that will be in the peak/ridge with black stump paint. That should keep things safe from the bugs and fungi.