Leaking chimney stack on roof in Asheville NC
We got Called out to look at a chimney leaking after another roofer Failed to fix the problem. Due to the amount of caulk on this area and the two different types of flashing used on this chimney stack, we recommend a very thick coating for this area. Once it’s completely coated, there will be nowhere water can get in.
As you can see in this photo, there is black plastic flashing, aluminum flashing, and a lot of caulking. It's not instantly apparent where the leak is coming from. Reflashing this stack is a challenge to do correctly as it's not a typical roof material.
As you can see, there is a red outline around the flashing. This is where we will tape off the roof making a nice straight square box. We will add a thick layer of ALDO roof coating to the inside of this area, completely coating this roof section. We will then remove the tape for a good clean line. 
As you can see in the picture, gaps in the foam ridge liner need to be sealed off due to blowing rain. We would address all of these whiles on the roof
This pipe boot looks like it's seen better days. In all honesty, it's the wrong kind of pipe boot for this roof, but if it were also sealed off with ALDO, it would last several more years! We would tape the area in red, coat the roof and then remove the tape for a nice clean edge. 