How to tie in existing roof to new addition

[hnash53]

I am thinking about adding on to my cabin (Nash cabin in Gallery).  

The question I have is how to tie in the existing roof with the new addition.  The new addition will be at right angles to the existing cabin.

Any diagrams or links to pictures showing how to do that would be great.

Many thanks.

Hal

[glenn-k]

Fill in the red space with a cricket.  Continue the ridge and rafters until the new roof meets the old one.  You will have to cut the shingles on the existing roof and flash under them or rework the valley with flashing and new shingles.  A few do a weave on the valley but it is a bit hard to make it come out right.