Adding Onto A Gambrel Roof . Continue adding pieces along the edge of the roof to the far end. Existing shed has a gambrel roof with ridge running parallel to the addition. 20 Examples of Homes with Gambrel Roofs (Photo Examples) from www.homestratosphere.com The shingles should be laid starting from the bottom of a gambrel roof. The classic gambrel is the most popular type of gambrel roof out there. Gambrels consist of two symmetrical roof sides with slopes in opposite directions.