How To Tie A Gable Roof Into An Existing Roof. Adding a gable roof to an existing roof tying a gable roof on an existing roof is a long and expensive project gable roof design patio roof building a porch. After the addition roof is framed and sheathed, snap a line on the existing roof shingles 2 in.

Tie into the end of an existing gable roof by removing existing facing boards, wall siding and any other obstructions back to the first truss of the old roof. Knowing local building codes avoid further hassles before you start your project, you should know about the local building codes and other permit requirements. Tie into the end of an existing gable roof by removing existing facing boards, wall siding and any other obstructions back to the first truss of the old roof.