You would think a flat roof would be easy, (I did) but they are not. We have changed how we approach them over the years. I recently had a request for help on the Woolworths flat from the “brick and mortar” disc and worked up this illustration. I think it helps clarify the basic concept we are using now. In general walls will have a tab that bends back and is glued under a coping tab which is attached to the roof art. This in turn might be capped with additional coping of stone or tile.