DIY Couch Cushion

Foam

• You can try to salvage the old foam from your couch cushion, but if it looks shoddy, buy new foam. Look for high-density foam sold by the yard that has the same thickness as the existing cushion--typically 4 to 6 inches thick.

  Use the old cushion as a pattern--if it's in one piece--to outline the exact fit onto the new cushion foam, and cut it out using an electric knife, a jigsaw or a handsaw. To add even more body to your cushion, wrap it with two or three layers of batting before inserting it into its new cover.

Simple Cushion Cover

• Take the width, length and thickness measurements of your cushion and add together the thickness measurement times two, plus the width measurement times two. This is the total width of your fabric when opened and laid flat. Before cutting, add 1 to 2 inches to allow for the seams. The length measurement for the fabric is the thickness times two plus the length with about two inches added. Sew the cushion cover to fit snug over your cushion and to keep the fabric smooth.

  The simple cover is finished by folding it in half lengthwise and on the wrong side, and then sewing the open sides closed, leaving the middle section of the seam opened wide enough for the foam to fit inside. The four corners are then squared. Pull open the corners and stitch them across to the length of the cushion's thickness measurement. This will give your finished cushion a simple boxed finish.

Boxed and Welted Method

• This is a step up from simply boxing the corners of a simple square. In this method, a top and a bottom panel are cut out of the upholstery fabric to the width and length of the sofa cushion. The thickness of the sofa cushion and the perimeter of the sofa cushion are the measurements used to cut the cushion's side panels. All pieces are cut with at least an inch added for seam allowance.

  The side panel is outfitted with a long zipper that will allow you to zip it open and remove the foam for cleaning. The zipper is sewed in place at the position on the side panel that will be facing the back of the sofa.

  The welt or piping--fabric-covered corded edging--is sewed in place around the perimeter of the top and bottom panels with all raw edges together and about 1 inch from the edge. The top and bottom panels are pinned in place to the side panel--all on the wrong side of the fabric--and the pieces are then sewed together. When the cover is turned inside out and stuffed with the sofa cushion, it will look like new.