Assemble and decorate house. On foil-wrapped cake circle, using tip 4, attach front, back and side panels with icing; let set. To support roof, cut a 2 x 3 1/2 in. long piece of cake board and bend in half. Attach roof panels, centered on each half of support, with icing. Position roof on assembled house. Pipe tip 4 seam on top peak; let set. Remove roof from house and let dry, standing on a side edge.