I attached these front and back on the door side of our trailer. Using tin snips I trimmed the gutter for a better fit to the edge of the roof. Used PL Premium construction adhesive to bond the gutter to the edge and taped the gutter while the adhesive cured. I installed these three years ago, still going strong. Recently I used some grey caulking to cover up the beige adhesive. Made it look a bit nicer.