4. Insulate While You're at It
Code calls for insulating the voids between the garage ceiling and the addition's floor, but Brewster and Tiplady also recommend adding insulation to unfinished garage walls before drywall goes up. "Anything you can do to keep this area a bit warmer will help the new room feel more comfortable," says Tiplady. At Geoff and Michelle's, open-cell spray-foam insulation was used to form a barrier against the area's strong winds, with the new bedroom's floor surpassing the required R-30 rating.