How to Replace a Porch Door

Measure the width and height of the door and order a replacement door to fit those dimensions.

Take out the pins holding the old door to the hinges by prying the pins out from the top or tapping them upwards from underneath with a hammer and nail. Have someone hold the door in position while you remove the pins so the door doesn't fall on top of you.

Slice through the caulking that surrounds the door frame with a utility knife to minimize damage to the wall and make it easier to remove.

Pry the doorjamb off the doorframe with a hammer and chisel, and then pry the outside casing off of the wall. Be careful when doing this so you don't damage the wall.

Slice through the nails holding the door frame in place with a reciprocating saw. There should be three or four nails on each side.

Lay a level on top of the threshold. If it's not level, nail shims to the threshold every 6 to 8 inches until it's level. Trim the shims with a utility knife.

Place adhesive-backed aluminum tape on the threshold.

Apply two thick beads of silicone caulk on top of the aluminum tape and along the inside edge of the door frame.

Set the bottom of the new door into position on the threshold and move the top of the door into place. Affix the door in position temporarily by driving two nails halfway into the flange in the upper corners.

Measure diagonally across the doorframe and compare the measurements to check for square. If the measurements are different, install shims around the door frame until they match.

Check the doorframe for plumb (vertically straight) and level (horizontally straight).

Measure the margins between the doorframe and the door on both sides of the door. Place shims into the gaps to even it out, if needed. Trim any shims installed with a utility knife.

Drive nails every 6 to 8 inches into the flange around the door.

Place aluminum tape on top of the nailing flange on the door's exterior.

Cut a 2-by-4 board to fit across the top of the door frame. Glue a drip-cap to it with carpenter's glue.

Nail the drip-cap and side trim alongside the door on the exterior of the house. Apply a thick bead of caulk around the exterior of the trim to make it waterproof.

Apply primer to the frame and allow it to dry, then paint the frame and allow the paint to dry.

Insulate the interior wall around the doorframe with fiberglass insulation or spray-foam insulation. Place the interior casing into position around the frame.

Install the door lock.