Sometimes the foam in your couch cushions breaks down making the once soft cushions no longer comfortable to sit on. If the fabric upholstery and the frame of your couch are still in good shape and you do not want to invest in a whole new couch, consider refilling just the couch cushions. Purchase all the items you need from a local fabric store. It will take only a few minutes of your time per cushion. Then your couch will once again be comfortable to sit on.
Take careful measurements of your couch cushions before buying the foam. Measure the length, the width and the depth. Jot down the measurements.
Purchase the necessary foam from the fabric store. Make sure to purchase conventional foam for indoor seating instead of spending extra money on special outdoor foam, unless of course, the couch is outside.
Draw around the old cushion or measure and mark on the foam where you want to cut to make the individual cushions. Draw out the whole square on both sides of the foam so you can be sure of where to cut perfectly. Do not worry about the marker, because you will not see it after you put the cover back on it.
Use the electric knife to cut the foam into individual cushions if the fabric store gave you one long piece. Cut the foam as straight as possible to make your cushions look their best.
Remove the old foam from the cover and throw away. Wash the covers, if they are not dry clean only, before adding the new foam. Allow to air dry to prevent shrinkage.
Insert the new foam into the clean covers. Work the corners of the cushion into the corners of the cover. (Be patient as this may take a few minutes to get it to look right.)
Keep in mind that most of the measurements of your couch will remain basically the same, except for the depth. Often, as cushions wear out, the foam looses its density and is not as thick as it once was. Purchase foam that is an inch thicker than what you measure to make up for the loss. If you do not have an electric knife to cut the foam with, take your exact cushion measurements to the fabric store and ask them to cut the individual foam cushions for you.