How to Frame an Interior Wall in a Finished Space

Find the ceiling joists, using a stud finder. If your wall will be running parallel to the ceiling joists, choose a location for your wall that runs directly beneath a joist. If your wall will be running perpendicular to the ceiling joists, you may place the wall anywhere.

Mark the location of the wall with a pencil. If your wall is running perpendicular to the ceiling joists, mark the location of all ceiling joists with an “X.”

Measure the length of the wall and cut three pieces of lumber in that size.

Attach one of the pieces to the ceiling, in the place you marked where the wall will be. Use 3-inch screws. To make this easier, drill pilot holes slightly smaller than the screws.

Lay the remaining two pieces of lumber flat on the floor, side by side. Clamp them together. These pieces of lumber are the top plates and bottom plates of the wall.

Measure a space 1.5 inches long from one end of the pieces of lumber. Mark this length with your pencil, then draw an “X” through the 1.5-inch space. Sixteen inches down from that “X,” measure another 1.5-inch space and draw an “X” through it. Each “X” represents location of a stud along the bottom and top plate. Repeat this step until you reach the other end of the plates. Mark the other end of the plates with space for three studs, all in a row, even if this means the space before these studs is not 16 inches long.

Measure the distance between the piece of lumber you screwed to the ceiling and the floor. Subtract 3 inches. This is the length of the studs.

Cut the lumber for the studs. You will know how many studs you need by counting the number of places you marked for studs on one of the plates.

Nail the studs between the top plate and bottom plate in the places you marked for studs.

Place the frame upright and slide it into position beneath the piece of lumber you screwed to the ceiling. The side of the frame with three studs positioned in a row should be set away from the existing wall in the room.

Nail the frame to the piece of lumber you screwed to the ceiling and to the floor.