Preparation

• Make sure that the area you are going to be flashing and applying shingles over is clean, dry and free of debris. Remove or pound any obtrusions flush with the surface of the rooftop.
  
  Always be extremely careful when working on a rooftop. For very steep roofs, wear a safety harness to prevent falls.
  
  

Installation

• Start fastening your roofing shingles at the base of the roof using galvanized roofing nails. When you reach the exposed stovepipe, set the lead jack in place to check the fit. You want the flange of the lead jack to extend onto the exposed part of the shingle course it will overlap. If it doesn't, affix another course of shingles. Set the lead jack aside and fasten the shingle course the jack will overlap. Cut away with a utility knife the top end of the shingle where it runs into the stovepipe.
  
  The jack will overlap one course of shingles, and will be overlapped by another. After you've gotten the lower shingle course fastened, set the lead jack in place. Fasten the shingle course that will overlap the lead jack. You will likely need to cut away some material from the butt end of a shingle in this course where it runs into the stovepipe, now housed within the tubular portion of the lead jack.
  
  Once you've got the lead jack fastened and locked in with the shingles, fold the top ends of the tubular sleeve inside the stovepipe opening. This will complete the water-resistant shell.