The chimney flashing is leaking in a corner. We had this repaired about 4-years ago by a reputable contractor, but the problem is back. Actually, it's not as bad as it was. Before, it was leaking so bad that the wall began to stain from the inside out. Now, it's localized to the corner of the ceiling. I've been looking for some "How to" info so that I can see how a chimney flashing system is designed. I want to do the work myself. Could you please direct me to a website with this info, or provide it yourself. Though I've been doing a lot of research lately on roofs, I have no practical experience, other than replacing some missing asphalt roofing shingles on my home. It made no sense to have a chimney here in Florida. It's not worth the headache.