Hanging a new door can seem a complex operation, especially if the original door was a non-standard size. Purchase a door within the next largest out there size so that it may be cut down to fit. Choose a good quality door, and consider if a fire proof door is necessary. In somce cases you should consult local building regulations prior to deciding on the type of door to fit your property.
Secure loose door frames by drilling a hole through the frame, then switch to a masonry drill bit and drill on into the masonry behind. Insert a lengthy plastic frame plug and screw the frame securely to the masonry.
Ease doors that get stuck in their frames at the top by chamfering the top edge slightly with a plane.
Cut out rot within the bottom of exterior door frames and replace it with new wood.
Hinge screw heads that are not driven fully into their recesses will stop the door from closing. Replace the screws if needed.
Hinges set too deep in their recesses can also stop the door from shutting. Fit packing under the hinge leaf to cure the trouble.
If hinge screws work free take them out, drill out the screw holes and tap in a short piece of glued dowel. Make a new pilot hole and replace the screw.
If door bottoms stick slightly in solid floors, use sand paper to remove a little wood from the underneath of the door.
If the door bottom gets seriously stuck, remove it from its hinges and plane wood from the underside.