I was asked to do a cake for a New House for the couple, I thought of a stacked square with bc icing and bc icing for the doors and windows and then make the roof out of fondant how would i shape this roof , any ideals would be appreciated, dont need untill sept 28

If you are not wanting the roof to be actual cake, you could always use a dummy. You might even be able to find the right size square styrofoam at hobby lobby and cut it diagonally to make a triangle. That sounds like such a FUN cake to do! Can't wait to see it when it is done!

The first thought that came to mind was RKT covered with fondant shingles. Not sure what kind of effect you are looking for, but RKT is edible.