Covered patios are nice, allowing you to enjoy the outdoors without having to deal with the sun. However, the outdoor living area doesn't become completely comfortable once you cover it, since you still must deal with bugs. To combat the problem and create an area where it is possible to enjoy the fresh air without the interruption, consider screening in the patio. Use the existing roofing to help enclose the porch.
Measure the distance between posts on the porch. Transfer these measurements to 2-by-4s and mark them for cutting. Cut two boards to match the distance between each patio post. These are the top and bottom plates of each section on the patio. Use a power saw to make the cuts along the marked lines. Cut 1-inch strips of wood pieces to the same lengths and set them aside for later.
Put one of the cut boards along the ceiling between each post. Drill 3-inch screws through the boards and into the ceiling to attach them. Drill in two screws every two feet.
Place one of the other boards on the floor between each post on its 4-inch side. Put the boards along the outer edge of the floor of the patio. Drop a plumb line from the top plates to show where the bottom plates need to be to be directly below the boards above.
Drill pilot holes though the boards and into the concrete. Use a masonry bit to make the holes. Make holes in pairs every two feet along the boards.
Drill 3-inch masonry screws through the boards and into the floor to anchor the bottom plates.
Measure in between the top and bottom plates. Mark this distance on more 2-by-4s. Cut these boards for the studs in between the top and bottom plates. You want one on each side of the patio support beams and then again every three feet. Cut 1-inch strip wood pieces to the same measurements and put them aside for later.
Place the studs in between the top and bottom plates. Use a square to check the corners where the plates intersect with the studs to ensure that they are at right angles.
Drill 3-inch screws through the ends of the studs at an angle so that they go through the studs and into the top and bottom plates.
Roll out mesh between the studs. Tack it at the top with staples, then pull it tight at the bottom. Staple it at the bottom while it is taut. Finish by stapling the sides of the mesh to the studs. Repeat in between each stud.
Nail the wood strips to the 2-by-4s to hide the edges of the mesh. You have been cutting these strips in prior steps and setting them aside for later. Use finishing nails to hammer them into place.