Step 1
Measure the height of the couch to determine the size of your slipcover. Start at the back of the couch and place the measuring tape just under the edge of the couch on the rear side. Bring it up and over the back of the couch, down the front to the seat, across the seat and down to the floor. Stop measuring at the front of the couch, just under the edge. Add 3 inches to this measurement and call it Measurement A.
Step 2
Measure the width of the couch. Start on the left side, just under the edge at the bottom. Bring the measuring tape up and over the arm, down to the seat and across the cushions to the right. Go up and over the right arm and down that side, ending just under the edge. Add 3 inches and call this Measurement B.
Step 3
Use scissors to cut a large piece of fabric that measures A by B.
Step 4
Fold under the raw edges of the fabric by 1/4 inch on one edge, folding toward the wrong side of the fabric. Press this seam with an iron. Fold again by 3/4 inch and press again. Repeat this on the other three sides.
Step 5
Sew a straight seam along the inner folded edge on all four sides. Keep the very ends open to create a casing for the elastic on all four sides of the fabric.
Step 6
Measure the two short sides and the two long sides; cut a piece of 1/2-inch-wide elastic for each that is approximately 2 inches shorter than the actual measurements.
Step 7
Thread a length of elastic through the casing on one side of the cover. Use straight pins to hold the elastic onto the fabric at either end of the casing, gathering the fabric of the cover to accommodate the shorter length of the elastic. Repeat this with the other three sides.
Step 8
Bring the ends of two adjacent pieces of elastic together, removing the pins on this end. Overlap them slightly and insert them into your sewing machine. Sew a zigzag stitch back and forth over the ends to hold them together. Repeat this at the other corners.
Step 9
Pull the cover over your couch, letting the elastic ends secure themselves just under the edges at the bottom of the couch.
Step 10
Cut a length of PVC piping that is slightly shorter than the inner width of the couch. Insert the PVC pipe behind the cushions of the couch toward the inside; this will hold the slipcover in position between the cushions and back of the sofa.