How to Cover a Piece of Foam for Bench Seats

Measure the length, width and depth of your cushion.

Cut two pieces of fabric measuring the length of your foam by the depth of your cushion plus 1/2 inch. Cut another two pieces measuring the width of your foam by the depth plus 1/2 inch.

Put two strips together lengthwise with their right sides together and pin in place. Stitch one of the short sides together, leaving 1/2 inch at the top and bottom free. Stitch a length piece to a width piece; stitch that width piece to another length piece and finish by stitching the final width piece. You will end up with a square; the length pieces will face each other and the width pieces will face each other. This piece is the welt that goes around the foam.

Cut two pieces of fabric whose dimensions are the foam's length by width. Add 1/2 inch to all sides for seam allowances. These pieces will be the top and bottom of your cushion.

Place the bottom of the welt piece on the bottom cushion piece with right sides together. Match raw edges; the corners of the welt should match the corners of the cushion piece. Pin in place. Insert a zipper in one side; the zipper should be 2 inches shorter than the length of the bottom cushion. One side of the zipper will be sewn to the welt, and the other side will be sewn to the bottom cushion. Stitch the zipper in place, followed by stitching the other three sides of the welt to the bottom cushion. Leave the zipper open.

Pin the top of the welt to the top cushion piece with right sides together. The raw edges and corners should be matched together. Stitch in place. Turn the cushion cover right-side out through the open zipper.

Put the foam piece through the open zipper. Close the zipper.