How to Frame a Room in the Corner of the Basement

Determine the dimensions of the room to be framed. Snap a chalkline on the floor to outline the the two new walls to be framed. Note the location and width of the door and mark it on the chalkline.

Align a pressure-treated stud (sill) with the chalkline and mark the width of any door openings on the stud. Cut two studs to 80 3/4-inches (triggers) and lay them next to the sill plate at the door marks on the chalkline. Lay two standard studs (king studs) next to each trigger, outside the door marks. Cut a 2-by-12 header 5 inches wider than the door width. Lay it between the king studs, above the triggers.

Mark the sill at 16-inch intervals beginning at each king stud. Lay a stud at each mark.

Lay two studs against the studs, opposite the sill plate. This completes your wall layout. Repeat the layout process for the other wall.

Drive two nails through each stud and into the sill plate at a 30-degree angle. Nail the king studs to the triggers and to the header atop the triggers. Nail the top plates to the top ends of the studs.

Cut the sill plate from between the two triggers.

Raise the wall so that it sits on the chalk outline. Your may need to hammer the side of the top plate to wedge the wall between the floor and ceiling joists. Nail the ends of the sill and top plates to the sill and top plates along the existing outside wall. Repeat with the other wall.

Nail the top and sill plates of the two new walls together where they meet. Nail the sill to the floor with masonry nails.

Measure the spans between the vertical studs and cut a 2-by-4 into fire blocks to fit between two studs. Place a fire block between every two studs, halfway between the top and sill plates, and nail it to the stud to complete the walls.

Push the door frame into the rough door opening. Push wood shims by hand into the gap between the door frame and the wall framing until the frame will not shift when pushed from either side. Place the carpenter's level atop and alongside the door frame to check for plumb. Add or subtract shims as necessary until the door is plumb. Cut off the ends of the shims so that they are flush with the wall and frame.