How to Add a Screen Porch

Screened porches provide a wonderful way to commune with nature without the bugs. If fresh air, cool breezes, spotting fireflies and smelling honeysuckle are enough incentive to consider turning that patio or deck into a screened room, you will need to contact your local building inspector to determine the codes that pertain to your area. This is a large project that will exact considerable time and effort on your part. The following are general directions for adapting your specific plan to add a screened porch to your home.

Things You'll Need

• Basic carpentry tools
• Table saw
• Circular saw
• Miter saw
• Screen material
• Staple gun
• Lumber
• Lag screws
• Roofing material
• Ceiling material

Instructions

1. Formulate the plan for your screened addition. Check the local building codes, notify the utility companies of the location of your room and gather the appropriate materials and supplies for the project.
   For two-story houses, position the room so that the roofline, as it attaches to the house, doesn't cut into a window. For one-story homes, your design will tie into the existing roof.

2. Measure off the dimensions with stakes and string. Keep in mind standard lumber sizes to minimize waste and expense.

3. Dig holes for footings if you are using a deck-type floor for your addition. Six by six treated posts are adequate for the supports. If you are building a solid floor surface, dig footings, lay block or brick and have concrete poured.

4. Bolt ledger board to the house, if you are building a deck-type floor. You will need to remove a portion of the siding to attach the ledger board. Build the perimeter frame of double 2 by 10 joists. Mount joists to the ledger board with double joist hangers. Continue attaching single joists within the frame, spacing them 16 inches on centers. Pour concrete in holes and place 6x6s in place. Install decking boards for the floor.

5. Cut through the siding to prepare it for the vertical ledger boards. Install ledger boards with lag screws. Make sure the ledger board is plumb. This is where the side walls will attach to the house.

6. Build the frames for the side walls with 2 by 4s. Space vertical 2 by 4s about three feet apart. Two horizontal bands 10 inches from the top of the wall and 10 inches from the bottom of the floor, will provide enough screen support, according to Jeff Gorton, the Family Handyman. One wall will house the door. Frame it accordingly. You can build the sides framework on the ground and lift them in place when they are done. Screw in place.

7. Make the trusses or buy them already made. Attach one truss to the house. Remove siding if necessary or screw directly into brick with concrete anchors. If you are tying into your present roof, you will need to cut away the overhang and rafter tails and install a truss plate on which to attach the first truss. Attach remaining trusses.

8. Cover the roof with plywood, tar paper and shingles or another material of your choice. Screen the gable end or finish with siding. The inside ceiling can be fastened to the rafters or ceiling joists, as you wish.
   Wiring for lighting or for a ceiling fan should be done before the ceiling is finished.

9. Cut panels of screening to fit the framing and staple. According to Jeff Gorton, start at the corners, stretch screening slightly and place 1/4 inch staples every 3 inches. Cut 2 by 2s to use as batten along the frame to cover the staples. Screw or nail in place.

10. Install the screen door with hinges and latch. Trim frame as necessary to fit.

Tips & Warnings

• Paint the 2 by 4s, 2 by 2s and any exposed rafters before assembling the frame. A pair of sawhorses can make this job go quickly.

• Screen porches get wet. The floor should be sloped. For wood, slope the floor 3 inches for every 12 feet, for concrete 1 inch for every 12 feet.

References

• The Family Handyman, Construct a Screen Porch
• This Old House, How to Add a Porch to a '60s Rambler
• Screened Porch, Extreme How-To