How to Make a Gingerbread House with Royal Icing

Run a bead of royal icing on all edges the roof will touch. First, place one roof side on the gingerbread house, making sure it lines up with the gable peak. Hold a few minutes. Then, while still holding the first roof side, add the second roof side and hold a few minutes. While still holding both roof sides, run a thick bead of royal icing down the seam where the roofs meet at the top. Hold a few minutes more and release. If your royal icing was made correctly, it should adhere with no problem.