Cover front of roof with gray fondant, secure with damp brush and trim. Cover window with fondant and decorate as for tower. For rooftop, roll out black fondant 1/8 in. thick; cut a 14 x 3 in. strip. Attach to roof with damp brush; trim. Using knife, mark sections 3/4 in. wide on roof, then score to resemble wood grain. Using royal icing and tip 3, add scallops on eaves (smooth with finger dipped in cornstarch).