Regular white frosting may look pretty on the roof, but it won't hold the pieces of the house together. For that you need "royal icing" that is extra stiff and dries hard. I usually make it with meringue powder, but I think some recipies use egg whites. I'm at work so I don't have any recipes with me, but I'm sure a quick google search would help you find what you need. Good luck! We used to make these every year, but we usually just bought a kit. By the way, have your camera ready!