Things You'll Need
Door, door hardware and trim
Basic carpentry tools
2 x 4 lumber
Framing nails or deck screws
Wiring supplies (optional)
1/2-inch drywall, compound and tape
Drywall installation and finishing tools
If you really need more closet storage and are willing to give up some floor space to get it, a corner closet is often the best option. All it takes is framing up a wall or two, finishing it with drywall and adding a door. A square or rectangular closet requires two walls, while an angular design needs only one. The disadvantage of an angular closet is that, while it occupies less room area than a square-cornered design, it yields a lot less closet space, particularly for hanging clothes. Because the walls of a corner closet are non load bearing, you can build them with a basic 2 x 4 frame. You can also use steel studs, although wood framing is better than steel for anchoring shelves and hardware. Be sure to buy your closet's door before you begin building, so you'll know exactly what size to make the rough door opening.
Locate and mark the wall studs and ceiling joists in the project area, using a stud finder. Plan the closet size and configuration so that the wall frames can be anchored into existing studs and joists. For hanging space, make the closet at least 30 inches deep (after drywall is installed).
Lay out the walls on the ceiling. Mark the outside edges of the wall frames at each end, then snap chalk lines between the marks. Use a framing square to confirm that all walls are perpendicular to each other and to the room's walls. If not, adjust the chalk lines as needed. For an angular closet, lay out the wall frame at 45 degrees to the existing walls.
Transfer the wall layout lines down the walls and along the floor, using a 4-foot level.
Cut a 2 x 4 top plate and bottom plate for each wall. Fasten the plates to the ceiling joists and floor, respectively, using framing nails or deck screws.
Mark the stud layout onto the plates, spacing them 16 or 24 inches on center. If desired, plan for additional studs to serve as backing for shelves and hardware. Mark the layout and cut the studs for the door opening.
Install the studs with framing nails or deck screws. Add a header and "cripple studs" to complete the door frame. Also install any wiring and electrical boxes for new light fixtures, switches or receptacles.
Cover the walls with 1/2-inch drywall, and finish the joints with paper or mesh drywall tape and drywall compound. Finish outside corners with corner bead or wood (or other) trim.
Install the door as directed by the manufacturer. Paint the walls and add door trim, as desired.
Finishing drywall at an inside corner between new and existing walls is tricky and time-consuming. As an alternative, you can butt a flat (not tapered) edge of the drywall sheet tight against the existing wall, then use a neat bead of paintable caulk to cover the joint. The same technique works just as well for wall-to-ceiling joints.
Check with your city’s building department about permit and building code requirements for your project. Some codes require light fixtures for closets.
Shut off the electrical power to all circuits in the project area and check for wiring, plumbing and other lines before fastening or penetrating any existing wall, ceiling or floor surfaces.