my new garage i have to turn the existing outside door into a fire door between garage and kitchen. I want to use the existing frame if i can. It is an all in one unit almost like an L shape. The door stops are part of the frame. Would this be ok to use, i believe i need to increase the door stop to 25mm(?) as it current is about 12mm, can i just nail and glue an extra piece of wood on for this. I will upload photos if i need to, thanks