Working one side at a time, use an Angled Spatula to place a dollop of icing on a roof panel. Use enough icing to cover the surface. Alternately, if using an icing pouch from a kit, pipe enough icing to fill-in the roof panel.
With a back-and-forth motion, spread icing to cover the roof panel. Remove any excess icing from the spatula.
Once the roof is fully covered, run the spatula lightly over the icing in the same direction, blending for an even look.
Clean the edges of the roof panel using the side of the spatula, scraping any excess icing gently. Remove any excess icing from spatula before cleaning the next edge.