Frame the Coat Closet
Locate the coat closet near the front door. Measure the floor area available--its length and width--and cut pieces of 2-by-4-inch wood with a compound miter saw to mark the closet's outline onto the floor. Cut another set of pieces for the top of the closet's framing and set it aside. Leave an opening as wide as your closet door plus an additional 1¼ inches for the door framing.
Pre-drill screw holes through the wood and into the floor underneath. Use a hammer drill to drill if the floor is concrete. Put anchors into the holes and screw the base plate to the floor.
Screw the top plate to the ceiling along the same outline as the base plate. Connect the top plate to the ceiling joists with screws.
Measure the vertical distance between the top and base plates for the closet walls' wood studs. Cut several pieces of wood studs and space them every 12 inches. Nail them into the top and base plates with a nail gun.
Frame the Closet Door Opening
Measure two pieces of the 2-by-4-inch wood studs to 82 inches and cut them using a compound miter saw. Flank the door opening with these studs on both sides and nail them into the wall's wood studs.
Cut a piece of 2-by-4-inch wood using the horizontal measurement from the top of one vertical wood stud to the other wood stud for the door. Nail it into the wood studs at both ends.
Cut three to four short pieces of 2-by-4-inch wood using the measurement between the top plate and the base of the door header. Insert these pieces into this space, space them evenly apart and nail them into the top and base plate.
Hang the door by screwing one side of the hinges to the door and then screwing the other side of the hinges to the door framing. Use a chisel or router to recess the hinge plate into the door framing.
Chisel out a hole into the door framing for the door latch and screw the strike plate over the hole.
Sheetrock the Walls
Cut pieces of sheetrock to completely cover the outside and inside walls of your closet. Measure the wall's height and width and transfer this measurement to the sheetrock.
Score the lines with a straightedge and a utility knife, and snap the sheetrock into two by bending it on the line.
Cut through the underside of the sheetrock with a utility knife to separate the pieces.
Line up each piece of sheetrock to the wall framing and screw into the wall studs using sheetrock screws. Make sure the edges of the sheetrock is on a stud and not into the empty space between the studs. Slightly recess each screw but not below the first layer of paper. Screw several screws along each stud 10 to 12 inches apart.
Smooth joint compound over each screw hole with a putty knife. Smooth joint compound over each seam, apply paper or joint tape over the seam and then smooth another layer of joint compound over the tape. Feather the compound to a smooth, seamless finish.
Install the Hanger Rod
Mark the position for the hanger rod onto the side walls about 62 inches up from the floor.
Cut two pieces of 1-by-4-inch wood, 15 to 18 inches long. Nail or screw each piece to the left and right side walls in the closet 62 inches high.
Screw the hanger rod hardware near the lower edge and at the center of the 1-by-4-inch wood pieces.
Measure the width of the closet from one hanger rod support to the other, and cut the hanger rod down to this measurement.
Insert the hanger rod into the hardware and place coat hangers onto the rod.