Repositioning or relocating the interior door framing in a wood frame structure is a simple procedure that requires a little rough carpentry. The door and door frame are installed in a rough opening in the stud wall. Shifting the door location means removing the door frame, dismantling and rebuilding the rough opening, and installing or reinstalling the door unit.
If the position of the new rough opening coincides with the location of a column or post within the wall, the opening must be shifted to one side. A column provides major structural support and cannot be moved. A rough opening consists of a header acting as a lintel and 2 double trimmer studs. The header is actually 2 boards nailed side to side with plywood spacers in between. The boards vary in size from 2 x 6 to 2 x 12 depending on the width of the opening and the vertical load applied to the wall.
Plywood is inserted to give the header an overall thickness equal to the 4-inch thickness (actual size: 3 ½ inches) of a 2 x 4 trim board. The header is supported on each side by the trim boards – a full-length stud and a shortened “trimmer” nailed side to side and called a double trimmer stud. The bottom edge of the header will bear 1 ½ inch on the butt end of each trimmer.
Step 1 - Remove the Existing Door and Frame
Begin by removing the door frame from the rough opening. If you intend to salvage the door frame, pull the nails from the side jambs leaving as little scarring as is possible, and remove the door and door frame separately or as a unit. Remove enough sheetrock from both sides of the wall to show the existing rough opening and the location of the new rough opening. Remove sections of sheetrock so that the cut falls on the center of a stud.
If you are reinstalling the existing door unit or installing a door of the same size, you can remove the rough opening (trim boards and header) intact. If not, cut the bottom plate to length and frame in the existing rough opening, installing new studs and a section of wall plate where the door was initially while maintaining the 16-inch spacings to the adjacent studs. Patch in sheetrock over the filled-in opening.
Step 2 - Frame in the New Rough Opening
Mark the location of the trim boards for the new opening on the top and bottom plates. If you are re-using the existing rough opening, set it in position and toe-nail the trim boards into the top and bottom plates, and the header into the top plate. If you are rebuilding the rough opening, remember that the rough opening is always 3 inches wider and 1 ½ inch higher than the door, allowing 1 ½ inch all around for the frame. Assemble the new rough opening on the floor so that it can be tilted vertically into position.
Make a trimmer by cutting a full stud at a length equal to the height of the header plus ¼ inch. Set this shortened trimmer flush at the bottom with the end of a full-sized stud and nail them side to side to make a double trimmer stud (make 2 sets). If the width of the new opening is narrower, cut the existing header to size. Otherwise, construct a new header as described above. Lay the trim boards on edge facing each other at a distance equal to the length of the header and lay the header in place. Using #16 nails, nail through the outer surface of the full studs into the butt end of both header boards (avoid nailing into the spacer gap), driving 3 or 4 nails into each board.
Lift the assembled rough opening upright and set it in position between the plates. (Note: The trim boards can also be installed in the wall first without the header, forming pockets to fit the header on each side. The header is then slid into place and nailed-in.
Step 3 - Install the Door Unit
Using a level, check to make sure the trim boards are plumb in both directions. Also, make sure that the header, plates, and trim boards are all flush within the wall surface. Check that the width and height of the rough opening are accurate to within 1/8 inch, and measure diagonally corner to corner to ensure that it is square. Nail off the assembly as described above. Cut out the bottom plate the width of the opening with a reciprocating saw. Patch in sheetrock around the rough opening and install the door unit, nailing through the side jambs into the trimmer with finishing nails.