Remove the seat. Turn over the chair and unscrew the seat from the rocking chair frame.
Remove the upholstery. Use the back of the hammer, a flat-head screwdriver or a staple remover to pull all of the staples out of the bottom of the chair.
Replace the foam. Cut a piece of foam to size with a bread knife to replace the existing material if it is damaged.
Attach the foam to the seat with spray adhesive.
Wrap the foam with cotton or synthetic batting. Staple the batting to the bottom of the chair to secure it. Place staples opposite one another first, making sure the batting is tight, then proceed to staple around the entire edge of the batting.
Cover the batting with upholstery fabric. Staple the upholstery fabric to the seat in the same manner as you did the batting, checking to be sure it looks tight and secure from the front then proceeding to staple around the entire edge.
Attach the recovered seat cushion to the rocking chair with screws.