Mirrored closet doors come in every standard door style, including bi-fold, bypass (sliding) and traditional hinged versions. Bi-fold and bypass are the most popular styles for mirrored doors, as both offer large areas of uninterrupted mirror and are made to install in most standard closet door openings. When purchasing mirrored doors, get a high-quality track system and related door hardware. Mirrored doors can be quite heavy, and better systems offer greater stability and smoother operation with fewer maintenance problems than budget hardware. A do-it-yourselfer can install them by following the correct steps.
Measure the width and height of the door opening, and purchase doors and a hardware kit of the appropriate size. Bypass doors offer more flexibility in width sizing. If you can't find the right size in stock products, order custom-sized doors from many manufacturers.
Cut the upper track to fit the top of the closet opening, using a hacksaw or reciprocating saw. Position the track against the top of the door frame, and secure it with the provided screws. If you would like to conceal the track behind a piece of trim, hold the track back from the front edge of the frame 1 inch or so, as appropriate.
Install the bottom track (for bypass doors) or the pivot brackets (for bi-fold doors) onto the floor, using the screws provided. Make sure the bottom hardware is offset from the front of the door frame by the same amount as the upper track, so that the doors will be aligned with the sides of the frame (or offset an equal amount) along the length of the doors.
Mount the hanging hardware onto the doors, as directed by the manufacturer. For bypass doors, this includes wheels at the top and bottom of each door. For bi-fold doors, this includes a wheel at the top, inner corner of each inner-door section and pivot pins at the top and bottom outer corners of the outer-door sections (each bi-fold door is made up of two sections joined with hinges). If bi-fold doors come without the hinges pre-installed, install them now, following the manufacturer's directions.
Install the doors into the upper track and bottom pivot brackets or bottom track, as appropriate. Open and close the doors, checking the operation and the fit against the sides of the door frame; also check the gap between bi-fold doors when closed. Adjust the doors, as needed, by making slight adjustments to the wheels and/or pivot pins or brackets. It can take awhile to get the doors just right; if the door opening is out of square, you may have to strike a compromise between gapping along the sides of the frame and between the doors (just go with what looks best).