Things You'll Need
Flat pry bar
Reciprocating saw with metal cutting blade
2- by 4-inch lumber
4-foot carpenter's level
3-inch finish nails
2-inch finishing nails
Drywall tape and compound
Replacing interior doors changes the look of the room. In some renovation projects, the height of the door is also an issue. In some older homes, the doors are rather low. Replacing the door with a taller door requires removing the wall sheathing above the door. The project is easier to complete if done as part of a complete room renovation, including the removal of the drywall, plaster or paneling. Do-it-yourselfers with advanced carpentry skills and adequate equipment should be able to complete the project without difficulty.
Remove the door from the hinges. Use a screwdriver to force the hinge pins up and clear of the hinge before lifting the door clear and setting it aside.
Remove the door trim. Pry the trim pieces away from the wall with a flat pry bar. Remove the doorframe, also with a flat pry bar. Remove any nails that pulled through the doorframe with a hammer.
Cut through the drywall or other wall coverings on both sides of the wall above the door. This exposes the wall studs and framework above the door.
Cut through the junctions between the wall studs and the header. The header is the board or assembly of boards across the top of the door opening. Use a reciprocating saw with a metal cutting blade to cut through the point between the stud and the header, severing the nails. The header is resting on top of short studs, sometimes called cripples, which support it.
Remove the header and set aside. Measure the opening needed for the new door. Cut a piece of 2- by 4-inch lumber to fit above the cripple stud to increase total height of the cripple to the same height as the door opening required for the new door.
Place the header above the cripples. Nail in place with 16d nails angled through the header into the wall studs. The header is supported by the cripples, and the nails hold the header in place.
Place the doorframe of the pre-hung door in the opening. Check the doorframes for vertical level with a 4-foot carpenter's level. Use shims, wedge-shaped pieces of wood, between the wall studs and doorframe to straighten the door. Nail the doorframe in place using 3-inch finish nails.
Place drywall in the open wall space above the door on both sides of the wall. Apply drywall tape and mud to the seams. Apply any finishes or paint necessary to match the rest of the wall.
Add the door trim around the door on both sides using 2-inch finishing nails.