Are you struggling to control the growth of moss or lichen on your roof? There’s a pretty easy fix – just cut strips of zinc flashing (copper and lead work, too) and slide them under a course of roof shingles and it will kill lichen and moss that grows there. There area also premade strips available from Shingle Shield. The premade ones are much quicker and probably neater looking.
Here’s a ‘How To’ video from This Old House that walks you through the installation of the flashing to prevent the growth of moss.