More in Windows Walls and Doors
Modification of load-bearing walls is not a job for the inexperienced do-it-yourselfer. While the door can be installed fairly easily after modification, altering a load-bearing wall might literally "bring down the house." Additionally, be aware that many states require a permit to alter a load-bearing wall.
In this demonstration, support beams were added before the load-bearing studs were removed and a new door frame was built prior to the installation of the door.
Measure the width between the side jambs, the head jamb to the seal under the old threshold, and the thickness of the wall. The rough opening should be at least one inch wider and taller than the outside frame dimensions of the new door. Also, decide upon a right-handed or left-handed swing.
Check that your opening is plumb and level. With the shipping brackets still attached, carefully set the door in place, centering it within the opening. If necessary, add shims under the lower side jamb until plumb and level. With a carpenter's pencil, mark a line at the top of the door on the brick lintel, then carefully remove the door.
Run two thick beads of latex caulk along the sub-seal at the bottom of the door opening. Apply another bead in a zig-zag pattern between the two beads (Image 1).
Then, lift the door into the center of the rough opening, positioning the bottom seal first, then tilt the door into place. Check for plumb (Image 2) and shim the frame as necessary.
Adjust the shims and frame assembly until the jamb on the hinge side of the door is plumb in both directions. There should be a constant gap (about 1/8-inch) between the jamb and the edge of the door. After making these adjustments, temporarily nail the door in place through the hinge jamb near the hinge locations with 16d finishing nails, without driving the nails all the way in. Secure the door with cement screws at each shim location. Trim off excess shims using a utility knife and pry bar.
Remove the shipping brace, attach the long-anchor screws (provided with the door) through the hinges and into the door framing.
Seal by running a bead of paintable latex caulk around the entire door. Fill the holes left by the screws with wood filler. Once the caulk and wood filler have dried, install weather stripping at the base of door if necessary.