Every year I make a big heavy gingerbread house and have trouble getting my walls to stick together. Last year I discovered that if you microwave a humbug or piece of candy-cane for say 30s (or until it starts to bubble) and then quickly jam it between two walls (or use the two walls to crush it together) and smooth the melting candy into the cracks with a spoon, the walls will be very secure. Then you can add your icing at your leisure.
