How to Build a Floor Door

Remove any carpets or rugs from the floor where you will place the door. Turn on the stud finder and mark the location of the floor joists on the floor using a pencil or piece of chalk. Measure and draw a square 2 feet long and 2 feet wide on the floor, ensuring the corners of the square are over the top of floor joists.

Cut through the lines on the floorboards using a circular saw. Be careful that the floor joists are not cut while sawing. Lift away the flooring carefully and put it to one side. You will have a 2-by-2-foot hole in the floor with portions of two floor joists visible on opposite sides of the hole.

Measure the distance between the two floor joists using a tape measure. Cut two pieces of two-by-four to a length equal to the distance between the joists. Screw one two-by-four piece between the joists on each side of the trapdoor using 3-inch long galvanized deck screws and a hammer drill with a screwdriver drill bit attached. Only 1/2 an inch of the two-by-fours must be visible in the hole.

Arrange the floorboards you cut earlier into a 2-by-2-foot square, with the faces that had been visible on the floor facing down. Cut two pieces of a two-by-four to 20 inches long. Screw one length of a two-by-four 4 inches from each end of the square floor, measured down along the joints between each floorboard, using 2.5 inch galvanized deck screws. This forms the door.

Place the door into the hole so it rests on the floor joists and the two-by-fours. Screw two 1-inch utility hinges onto one side of the door, equidistant from the adjoining sides of the door. Screw a cupboard door handle to the opposite side of the door to the hinges, to make the floor door easy to open.