Abstract: The present invention provides for an apparatus for retrofitting an existing wooden door having opposing surfaces to upgrade the fire rating of the existing door. The apparatus includes a door cover steel sheet having a non-combustible insulating coating on an interior surface for coveting at least one surface of the door and a lock set reinforcement bracket having a non-combustible insulating coating on an interior surface for surrounding the lock set opening on an opposing surface of the door, the apparatus providing at least a twenty minute fire rating to the retrofitted door. In an aspect of the invention, there is provided a method for increasing the fire rating of a door having opposing surfaces.