The Ultimate Gingerbread House Glue
A quick Google search will provide a plethora of recipes for Royal Icing, used to construct a Gingerbread House. They are all pretty much the same with small variations in amount of water, which will always be a variable from day to day anyway.
I start with this recipe and tweak the amounts of water needed based on humidity and what I am need it for. Sometimes I want the icing a little thicker and dryer, and other times softer and wetter, and sometimes I’m flowing with the same icing by adding plenty of water to create a 20 second flow icing!