Decorate roof. Work one roof section at a time, beginning at the top edge. Use icing to ice 1 ¼ in. deep section. Let icing set 15 minutes. Press impression mat onto iced roof and remove. Move down ½ in. and repeat for three sections on each side. Roll out fondant 1/16 in. thick. Use impression mat to imprint designs. Cut the fondant impressions into shapes. Let dry 1 hour. Use icing to attach fondant and candy to roof peak, candy to roof, and to pipe icicles.