Over-the-garage additions have a huge impact on curb appeal since they often face the street and tend to be large; a typical two-car garage is 24 by 24 or bigger. "You don't want it to look like a bulky, tacked-on box," says Brewster. A few strategies that will help it appear seamless: Make sure features such as gables and windows are harmonious with the house's style; add facade details, like trim, to break up expanses of siding; and, if possible, schedule the project in tandem with an exterior upgrade, like repainting or re-siding. Brewster designed Geoff and Michelle's addition with a cross gable that extends along the full length of the house, which also allowed for an attic to hold mechanical equipment. For visual symmetry, she centered double windows over the garage door and a gable-end window over the window below.