Fixed sofa cushions refer to cushions that are permanently attached to the sofa. These types of cushions are a bit harder to refill because you cannot remove them from the sofa, and the cushions typically do not have zippers, which means the seam must be cut and resewed. Many types of stuffing and cushioning can be used on sofas, but memory foam is probably the most comfortable and durable.
Measure the length and width of the fixed cushions on your couch.
Subtract 2 from each measurement. For a cushion measuring 21 inches in length by 29 inches in width, the final numbers should be 19 by 27 inches.
Measure out the final numbers on the thick foam padding. Draw the edges with a permanent marker.
Cut the foam according the lines you have drawn.
Use the seam cutter to cut one seam on the cushion.
Remove all old stuffing.
Place two layers of the foam padding, one at a time, inside the cushion.
Add stuffing underneath the padding until the cushion is full or until it is comfortable enough to sit on.
Resew the seam.
You can sit on the cushion while doing this project to determine the amount of stuffing needed. You also can use other types of foam padding.