Construct the Frame
Measure the length and width of your closet area and mark its outline on the floor by drawing chalk lines.
Mark the position of your closet door. For a 24-inch by 80-inch door, mark an opening of 25¼ inches. The extra 1¼ inches leaves enough room for the 1-inch-thick door framing, the hinges and any imperfections in the width of the door.
Use the compound miter saw to cut the 2-by-4-inch wood into pieces that are long enough to match the length of the lines on the floor. Lay these pieces flat onto the floor and pre-drill holes through them using a masonry or concrete drill bit. Use a heavy-duty drill with a hammering function for very difficult concrete.
Insert anchors into the holes to strengthen the connection between the screws, the concrete and the wood. Screw the masonry screws through the base plates (the 2-by-4-inch wood) to secure the foundation framing of your basement closet.
Follow the same outline of the base plate to position the header plate of your closet's walls onto the ceiling. Cut several vertical 2-by-4-inch wood studs to frame the rest of the walls. Space these wall studs 12 inches apart.
Frame the Door
Cut two pieces of 2-by-4-inch wood to 82 feet long for the two sides of the door frame. Position these 25¼ inches apart at the door opening and nail them into the wood studs next to the door opening.
Construct a door header by cutting a 29¼-inch piece of the 2-by-4-inch wood and nailing it to the top of the doorway's vertical 2-by-4-inch wood pieces.
Measure the distance between the door header's base and the top plate on the ceiling, and cut four pieces of 2-by-4-inch wood to this measurement.
Insert them above the door, evenly spaced, and nail them to the header base and top plate on the ceiling.
Finishing the Closet
Install insulation between the basement closet wall studs. Staple the edges of the insulation paper to the wall studs.
Measure the width and length of each wall of the closet and cut the Sheetrock pieces to these measurements using a utility knife. Line up the Sheetrock to the wall, leaving a Â¼- to Â½-inch gap between the Sheetrock and the concrete floor. This gap is a precautionary measure to keep the Sheetrock dry in case of moisture in the basement.
Screw the drywall screws into the Sheetrock and wood studs using a power drill. Space them vertically every 6 to 12 inches on each wall stud. Line up the vertical edges of two meeting Sheetrock pieces to the middle of the wall stud to make the wall extra strong. Custom cut the pieces of Sheetrock to completely cover the inside and outside wall of the basement closet.
Apply joint compound over the screw holes and seams, add paper tape over the seams and feather the joint compound to a smooth finish.
Install the door framing and hang the door with door hinges. Install wood molding around the doors and along the base of the closet and paint the walls.