Things You'll Need
Pre-hung wooden screen door
2-by-4 framing lumber
16d framing nails
Adding a door to a screen porch can improve access to a yard or garden, but it requires altering a wall. Many screen doors now have metal frames, but a wooden screen door will be more suitable for a screened porch built with 2-by-4 or 4-by-4 lumber. Start this project by buying a pre-hung screen door, with hinges and latch fastened to a frame or jambs to be secured inside a rough door opening. Match the door to the porch framework; get a door with a full screen interior or with double screens with a horizontal support between.
Pick a spot to add a wooden screen door, with a full wall stud for one side. Measure the wooden screen door with a tape measure to figure the frame opening. Add 4 inches to the width of the pre-hung frame, to allow for stud framing on either side; if the screen door frame is 38 inches wide, the rough frame should be 42 inches.
Add another full stud, between the bottom or sill plate and the top plate of the wall at the outside of the rough opening; space it from the inside of the full stud on the opposite side. Brace the top plate with 2-by-4-inch studs set temporarily between the sill and top plate to secure the roof while the door opening is framed.
Mark the studs on either side for the height of the pre-hung door frame; measure it and add 4 inches for a horizontal header. Cut the inside stud in the frame opening to that height with a reciprocal saw. Build a header with 2-by-4 boards, laid with 4-inch faces together. Fasten these with 16d framing nails and a hammer and cut the header with a circular saw to fit between the outside framing studs.
Set the header in place between the two full studs and under the cut-off top stud. Use a level to set the header level and fasten it with framing nails through the side studs and two nails driven up into the bottom of the short stud on top. Measure from the bottom of the header to the top of the sill and cut two studs to fit. Nail these to the side studs and toenail them with diagonal nails into the header and sill.
Cut the sill plate out on the inside of the two trim studs with reciprocal saw. Remove the temporary braces once the rough frame is completed and install the pre-hung door in the rough frame.
Remove any siding, screening or drywall to expose the porch studs or posts before starting the door frame. Replace siding, screening and drywall once the screen door is installed and trimmed.