How to Frame an Enclosed Porch

Decide what sort of enclosure you want. Design it to fit pre-built windows or screens or with full walls that have windows in them. Use as many pre-built elements, such as pre-hung doors, as possible. Place all these in a plan specific to each wall. Measure the wall opening, transfer the dimensions to graph paper and lay out the door and window openings and wall studs for each wall.

Work with the porch floor, either concrete or wood, and the existing roof. Build basic walls with a top and bottom plate and studs with centers at 16-inch intervals, around door and window frames. Lay out the plates and end studs of 2-by-4-inch framing lumber on the porch floor or other flat surface. Measure the height of the wall and cut the studs 1/4-inch short with a circular saw to allow room for installation of the finished wall.

Nail the corner studs to the plates with 16d framing nails and a hammer, two nails on each end of the studs. Square the wall: Use a framing square and measure corner to corner with a tape measure and adjust the boards until all four corners are square and the diagonal measurements are the same.

Install interior studs and door and window frames. Measure 15 1/4 inches from the end of a wall to set the second stud, then measure 16 inches for the next stud and so on down the wall; this will space the centers 16 inches apart. Build rough frames for doors and windows separately, with horizontal headers at the top and footers at the bottom of window openings, supported by short studs on each side. Place those elements in the wall and fasten them with nails into the adjoining studs.

Raise the walls inside the porch and slide them into place between the floor and outside roof bands. Plumb the walls with a level and make sure they are straight along the sides of the porch. Snap a chalk line to mark the bottom plate as a guide. Drive tapered wooden shims under the bottom plates at all stud locations to force the wall tight against the roof edge; alternate sides, one shim from the outside, the next from the inside. Make sure the wall is secure.

Fasten the bottom plates to the porch floor with 16d framing nails for wood or 3-inch concrete nails for a slab floor. Nail the top plates to the roof band with framing nails. Install pre-hung doors and pre-built windows at appropriate locations. Nail them in place to the studs of the rough framing around them.