If your couch has started looking and feeling old and worn out, then you can rev it up just by replacing its cushion foam. Actually, cushions have foam rubber inserted in them that are typically made up of polyurethane foam. With time, this foam breaks down and loses its firm feeling. This is when the need to replace your couch cushion comes.
If you are considering your couch cushion replacement, then first of all, get the exact measurements of your cushions, including their width, length and thickness. Then, you can order the new foam. You must know that a big 6 feet block of foam may be cut to accommodate multiple couch cushions. Cut the foam as per your required size with a carving knife, stuff the foam in your cushion covers and place them in place of the old cushions.
After doing this, you will have all new cushions for your old couch.