How to Build a Screened-in Porch From Scratch

Build the Porch

1. Dig Holes for Footers

   Dig three footer holes 6 feet away from the house, with the two end footer holes 12 feet apart. Position one hole directly in the middle. Dig below the frost line. Disperse about a half bag of landscape gravel per hole, or about 6 inches deep.

   Tip

   The frost line varies by region: Check with your local building department for the frost line depth in your area.

2. Add Form Tubes and Concrete

   Place the form tubes in the holes, checking that the tubes are plumb before and after the concrete is poured and packing dirt in around the tube to hold it in place. Mix the concrete and pour it into the form tube, embedding the metal column bases at the top in the wet concrete.

3. Attach Posts to Footers

   After cutting into sections, the six-by-six lumber will rest on the footers. Calculate the cuts based on the eventual height of the porch flooring:

   • 9 1/4 inches of height for the true height of the two-by-ten joist lumber
   • 1 1/2 inches of height for the porch flooring
   • Height to account for the drop in flooring from the house to the leading (outside) edge of the porch floor, about 1 inch.

   Cut and then attach the three posts vertically to the footer bases.

4. Attach Ledger

   Attach the ledger board to the side of the house by first removing the siding from that section. Use the laser level to determine the level of the ledger board. Use a multi-tool to cut out the siding. Drill pilot holes, then attach the ledger board to the house studs with the ratchet wrenches. Caulk around the ledger board to form a weatherproof seal between the ledger and the siding.

   What Is a Ledger Board?

   A ledger board or ledger is a horizontal board that attaches to the side of the house to provide partial support for porches and decks.

5. Build Porch Perimeter

   At each end of the ledger board, attach a double joist hanger. Attach the two 12-foot two-by-tens (doubled up) to the metal footer bases at the rim joist. Attach two more double joist hangers to the rim joist, facing toward the house.

   Cut the remaining two-by-tens into four 6-foot boards. Double up two by nailing them together. Add the double-side joist at each side of the porch.

6. Attach Porch Joists

   Each porch joist will be a single two-by-ten, 6-foot-long. Attach joist hangers on the ledger board at every 16 inches on-center. Repeat on the inner side of the rim joist. Insert the two-by-ten joists into the joist hangers and fasten by nailing them in.

   Tip

   Your local building code may require special nails or screws for attaching the joists and joist hangers. Check the requirements in your area before building, and look for these nails in the same section of your local hardware store where you found the joist hangers.

7. Install Porch Flooring

   Full-length 12-foot-long two-by-eights will form the porch flooring. Because the porch is 12 feet wide, you should not need to cut the boards. Screw the boards onto the joists with deck screws, leaving a 1/8-inch gap between boards.

8. Stain or Paint Porch Flooring

   Stain and coat the porch flooring with a clear protective coating. Or paint the porch flooring with solid color exterior-grade latex paint.

9. Optional: Add Railing

   If your porch is 30 inches or less above ground level, you may not be required to build hand railings. Requirements vary by community, so check on this first. Even if the porch is lower than 30 inches, you may still decide to add railings for appearance.

   Tip

   Note that, if you decide to build railings, the screen panels will be stepped back from the edge of the porch by about 4 inches.

10. Attach Roof Ledger Board and Hangers

    Cut away siding from the side of the house 9 feet above the level of the porch floor. Cut out a section 12 feet long and high enough to allow for the 2x6 rafters, 1/2-inch sheathing, shingles, and metal flashing—more than 5 1/2 inches. Attach a two-by-six to the side of the board with lag screws. Caulk all seams. Screw rafter hangers to the ledger board every 16 inches.

11. Install Roof Support Posts

    Set two 12-foot six-by-six posts 12 feet apart and 6 feet from the house. Set the posts plumb in concrete using footing tubes, just as you did for the footer bases.

12. Notch Supports and Add Header

    Use the Speed Square to measure your desired pitch of the porch roof, measuring down from the roof ledger board. A standard is 1:6, or dropping 4 inches for every 24 inches of horizontal run. With the circular saw, cut down and then notch the tops of the two-by-twelves to accept a two-by-ten header board (or 1 1/2-inch deep by 9 1/2-inches high). Screw the header beam in place with lag screws.

13. Install Rafters

    Cut the ends of the two-by-sixes to the correct angle, so that they seat in the rafter hangers and then angle down to and extend past the header beam to create a slight overhang. Nail the rafters into place in the hangers. Toenail the rafters to the beam.

    Tip

    You may need high wind hangers or clips to attach the rafters to the beam.

14. Attach Sheathing and Shingles

    Nail 1/2-inch exterior-grade plywood to the tops of the rafters. Starting at the front edge of the porch roof, install the shingle. Install an entire row, then work upward to the next one until you reach the house. Make sure to use shingles appropriate for the rise and run of the roof (less than 2 inches of drop per 12 inches of run).

15. Attach Drip Flashing

    Nail drip flashing between the porch roof and the side of the house, with the bottom of the flashing over the shingles.

16. Install Siding

    Install siding over the ledger, with the bottom of the siding overlapping the drip flashing.

Install Screens on the Porch

1. Plan Screens

   Once the porch has been constructed, it is time to add the screens. Screen panels attach to cleats built into the porch floor and ceiling. Each screen panel is 4 feet wide by 8 feet tall (or the height of the porch ceiling). So, each screen panel will cover 4 linear feet of porch. Thus, a 32-foot porch requires eight panels.

2. Install Cleat on Floor

   Attach a 4-foot-long two-by-two to the floor of the porch. If the porch has no railings, push the cleat to the very edge of the porch flooring. Drill pilot holes first, then attach the cleat with the 2 1/2-inch screws. Attach to the floorboards. There is no need to drive the screws into the joists.

   If the porch has railings, step the cleat back at least 4 inches from the railing.

3. Install Cleat on Ceiling

   Attach another 4-foot two-by-two to the ceiling of the porch. Use the plumb line or the laser level to establish a plumb vertical line from top to bottom.

4. Cut Boards for Screen Frame

   Using the electric miter saw, cut one of the one-by-twos to 45 inches. This will give you two 4-foot boards.

   Use the tape measure to measure the distance from the top of the floor to the bottom of the ceiling. Use the resulting measurement to cut two more of the one-by-twos to length.

5. Build Screen Frame

   Construct each screen frame with two vertical pieces of one-by-twos on the sides, with two horizontal 45-inch pieces between them. Construct each frame with the 3-inch wrap metal corner braces, using the included screws. Check each with the Speed Square.

   Tip

   Be sure you purchase wrap metal corner brace, which wrap over two sides of the wood. This helps initially square up the frame and keeps it square in the long-term.

6. Add Center Horizontal Piece

   Cut another piece of 45-inch one-by-two. Insert this horizontally between the screen frame's vertical pieces, using the four remaining wrap metal corner braces. Choose a level that looks pleasing to your eye. Generally, you'll want to keep it in the 40- to 48-inch-high range, measuring from the floor upward.

7. Add Screen

   Have an assistant help you stretch and staple the screen material over the screen faces. Work incrementally, slowly drawing the material tight while stapling it. Avoid creases or folds.

8. Drill Holes in Screen Frame and Cleats

   Removable bolts, washers, and nuts allow you to install and remove the screens seasonally. Hold a screen panel against the ceiling and floor cleats. On the six-foot step ladder, drill two holes at top, through both the screen frame and the ceiling cleat. Insert two 3 1/2-inch bolts through the holes and add washers and wing nuts to the back. Repeat at the floor cleat.

9. Repeat Screen Panels

   The screen panel configuration can be scaled to fit your porch. Repeat the previous process until the porch is finished.

   While most screen units will be 4 feet long, this project has two exceptions: the 6-foot depth of the porch, or its sides. For this, construct two 3-foot screens (rather than one 6-foot screen) to span that depth.

   Tip

   If you intend this porch to be a pass-through porch and not just an attached sitting area with only a door to the indoors, adjust your screen placement and any rails to allow for a door to the outdoors.

When to Call a Professional

Building a porch can be a difficult project, especially if you decide to use premium imported wood flooring or composite deck flooring or plan to include special features, such as multiple access points or elaborate screen arrangements. In many cases, you may want to call a general contractor or decking contractor to build the porch.