I need to replace my old apartment front doors (which are currently covered in asbestos on the inside!) The doors open off from an internal landing so I am proposing to fit fire doors with an Intumescent strip. I understand that I need to rebate the sides and top of the doors to sink in the strip but what do I do about the bottom of the door? The door frames are slightly awkward sizes so I may need to plane a bit off all sides, is this likely to be a problem. With regard to the fitting of yale type locks as these are usually fairly high up, what about finding a good fixing because cheap internal doors don't have anywhere to do this except for where the handle goes? Advice on type of door would be helpful. Finally, would it defeat the object of a fire door to fit a letter box? Any advice on the most cost effective way of doing this would be greatly appreciated.