1. Using the round tip and icing, pipe a line of icing on long bottom edge of a side wall rectangle and attach to the floor (E). Hold in place until icing is firm and the wall sticks to the floor. Pipe a line of icing on two adjoining sides of the front wall and attach to floor and first wall (F). Hold in place until icing is firm. Don't worry if a small amount of the icing shows. Pipe a line of icing along inside seams for reinforcement. Repeat until all four walls are constructed. Pipe a row of dots on each corner of workshop to cover the seams. Wait for 30 to 45 minutes to give the icing a chance to dry.
2. To give support to the upper front wall, stand a cracker rectangle at a right angle to center front of building. If cracker is taller than top of building, cut cracker to fit. Secure with a line of icing (G). Hold in place until icing is firm. Wait 15 minutes before continuing.
3. To attach the roof, pipe a generous line of icing on top edges of side walls, upper front and back walls, and vertical roof support. Gently press one roof rectangle in center position over a side wall. The roof will extend beyond the side walls (H). Hold in place until icing is firm. Repeat with second roof rectangle, being sure rectangles meet at the peak of the roof. Hold in place until icing is firm. Then, pipe a line of icing along peak of roof and where roof attaches to the walls. Wait for 30 minutes to let icing dry completely before decorating.