Mild weather means more time spent outdoors and on the porch. Porches are nature's free air conditioning, plus they let you chat with passersby. Unfortunately, mosquitos, flies, and other insects love pleasant weather and porches, too. Building a screened-in porch will help you regain that space—completely free of insects and other annoyances.
Before You Begin
Building a screened-in porch is a two-stage process. First, build the porch. Second, screen in the porch with detachable, modular screens. Viewing this project as two separate processes helps you to better budget your money, time, and energy.
You may even want to hire a contractor to build the porch, then complete the project yourself by constructing and installing the screens.
When to Build a Screened-in Porch
Pouring concrete footers for an elevated porch entails digging holes that extend below your area's frost line. During winter months when the ground is frozen, it can be difficult or even impossible to break through the frozen soil. If this is not a factor in your area, you can build a screened-in porch at any time of year.
Codes and Permits
Most communities will require you to obtain a building permit before building the porch. You'll also need to be aware of zoning restrictions. It's best to speak to your local permitting department before starting the build. It is not likely that a building permit will be required for adding screens. However, if your home is historically accurate and falls within a local preservation zone, in all likelihood you will need to obtain clearance before adding screens.
Call your local utility location service (811) ahead of digging footers for the porch. A technician will visit your property and mark the ground for critical electrical, gas, and water lines.
Equipment / Tools
- Post hole digger
- Electric miter saw
- Circular saw
- Framing hammer
- Caulking gun with exterior-grade caulk
- 3 concrete form tubes
- 2 bags base gravel
- 6 bags quick-set concrete
- 3 galvanized post bases for six-by-six
- 1 six-by-six
- 10 two-by-tens, 8 feet long
- 20 two-by-eights
- 1 two-by-two (per screen)
- 4 one-by-twos (per screen)
- 8 3-inch wrap metal corner braces (per screen)
- 1 metal or fiberglass screen 48-inch by 8-foot (per screen)
- 2 double joist hangers
- 10 joist hangers
- Deck screws
- 1 two-by-six, 12 feet long
- 2 six-by-sixes, 12 feet long
- 1 two-by-ten, 12 feet long
- 9 two-by-sixes, 8 feet long
- 1/2-inch exterior grade plywood
- Drip flashing
Build the Porch
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.
Add Form Tubes and Concrete
Place the form tubes in the holes. Mix the concrete and pour it into the form tube, embedding the metal column bases at the top in the wet concrete.
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.
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.
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 as 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.
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.
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.
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.
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.
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.
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 5 1/2 inches high. 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.
Install Roof Support Posts
Set two 12-foot six-by-six posts 12 feet apart and 7 feet from the house. Set the posts plumb in concrete.
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.
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 the header beam. Nail the rafters into place in the hangers. Toenail the rafters to the beam.
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.
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.
Install siding over the ledger, with the bottom of the siding overlapping the drip flashing.
Install Screens on the Porch
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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. In many cases, you may want to call a general contractor or decking contractor to build the porch.