Pry, chisel and scrape off old metal flashings and roofing cement. Before you do anything, get your ladder, roof brackets and safety harness set up so you can work safely and efficiently on the roof.

Flashing is a good way of preventing water from entering a dwelling at the point where the roof meets the walls. To begin the installation, fold a five-by-seven piece of aluminum flashing lengthwise.

First, remove the skylight’s counterflashing. On some units, you have to remove the whole glass frame. On other models, you simply unscrew a metal channel from the curb. Next, pry off the old shingles ...

Lee Wallender is a home improvement writer of nearly 20 years and specializes in home remodeling, repair and maintenance. Sami Allen is the managing editor at Forbes Home, with over seven years of ...