If you want your addition to look like it could be an original part of the house—instead of an afterthought—focus on the roofline. No matter how well the rest of the design blends and materials match with the house, unless you get the roof right, your addition will look like just that: An addition tacked onto the side of the house. There are four main roof options to consider: Roof Extension. If you're adding to the gable end of the house (the side wall that goes up to the ro