Okay here is the problem, I have a 4/12 pitch roof and presently it has butt shingles. Where the garage starts the roof has a very slight turn maybe 3-4 degrees( its like a mini valley towards the front of the house) . The past installer overlapped the joint and we do not like this. I have to put a new roof on this year and looking for ideas on what to do about this joint. I will be using butt shingles. Look foward to your input.