I was in the attic again last night and checked it out. I *think* what
is happening is that the older part of the house is sinking, as old
houses do, but it is sinking faster then the newer part of the house,
hence the crack (which would be counter intuitive if the new part was
putting weight on the roof). I say counter intuitive because the crack
has the board cracking "up" rather then down as if weight was pulling on it.

The /\ boards are normal boards until they get to about 3/8 of the way
down on the \ side. Then they get to about half width with a notch that
sits on the side of the old part of the house. The rest continues to
the newer part of the house. The crack starts at that notch with the
notch part sinking and the other part going up.

I'm not sure what to do now.. because do you really want to brace
something like that, as it might put pressure where pressure shouldn't
be.. as it isn't the new section is putting pressure pulling down and
needs braced, it's more the house is shifting... hrmm.

Someone is coming to look at it, we'll see what they say I guess.
Either way after looking at it it appears to really only be roof
support, so fortunatly it's not a huge deal, even if we need to replace
it (other then the cost).. we'll see what happens.


No wrote:
what TB said or a good carpenter or remodeler.

The \ could be craking for a number of reasons that no one can
determine from here.

Finished or unfinished space?
Pitch of the \
Snow loads?

Could possibly need a knee wall
/\
/ |\__
or new rafters, sistered next to old.

or both

This link has a picture of a knee wall. Site talks about insulation but
you will get the idea.

Question is - is this caused by the addition or not. Maybe, maybe not.

Is the _ part of the addition sitting on the \ or attached at he bottom
edge? If the bottom edge then I doubt the _ is causing the problem but
there is no way of knowing w/o proper assesment.

If it were me, based upon the limited info provided, I would sister new
rafters, bolt through then add a knee wall.