An upholstered piano bench that's worn, damaged or covered in a fabric that clashes with your sense of style does not need to stay that way. Revamp the bench by reupholstering it -- the old fabric serves as a cheat sheet or template, making it easy to figure out the exact size and shape of the material needed to complete the project. For best results, stick with an upholstery-grade fabric, otherwise the seat may wear out quickly and you'll have to reupholster it again.
Open the piano bench to reveal the hinges. Remove the lid from the bench by removing the screws in the portion of each hinge that attaches to the base of the bench, not the seat. If the piano bench does not open, skip this step.
Flip the seat, or the entire bench if the seat is permanently attached, upside down. Pull all the staples out of the upholstery fabric using a staple remover. If any of the staples are difficult to remove, use the tip of a flat-head screwdriver to pop them out. Leave the foam in place on the bench or bench top to reuse it; it should be attached to the seat.
Spread the new upholstery fabric face-down on a clean work surface or floor. Set the old fabric atop it to use as a template. Draw the outline of the old fabric onto the back of the new piece with a pencil, and then cut out the new material with scissors along the pencil lines.
Spread the batting out on the work surface, and set the new cut fabric atop it. Cut around the fabric to trim the batting to size.
Smooth the new fabric, with the batting on top of it, over the work surface to remove wrinkles, keeping the two materials lined up evenly with one another. Set the bench top -- or bench, if the top is attached -- face down atop the batting.
Press down on the bench top while grabbing the batting and fabric, together, on one long side of it. Wrap the fabric and batting around the underside of the bench top and staple it in place, using one staple every few inches. Repeat the process with the opposite side of the bench, pulling the material tightly before stapling so it has no wrinkles.
Wrap and staple one of the remaining two short sides, again pulling the material taut. Repeat the process on the remaining side.
Tuck and fold the corners and secure them with several extra staples, keeping the material neat and tidy, as if you're wrapping a gift. Trim away excess material near the corners, if necessary, using scissors.
Reattach the lid to the rest of the piano bench by lining up the hinge holes with the holes on the bench base. Replace the screws and tighten them with a screwdriver. Skip this step if the bench and bench top are permanently connected.
Pay attention to the hinged area of the bench, if your piano bench opens, to figure out how the upholstery originally worked around the hinges. Copy the same method for best results.
To give the underside of the bench a more finished look, cut a rectangle of coordinating fabric to cover the exposed area, centering it and stapling it in place where the top fabric ends.
If the bench is hinged, too much batting near the hinges may make the seat hard to open. Trim the batting from the hinge area when adding the new fabric to ensure the bench opens as designed.