Making Boxed Cushions

By Samantha Kuczynski March 7, 2024

Customize your easy chairs with this versatile technique

Cushions found on armchairs, sofas, and other upholstered furniture vary in style and construction methods, but the most common and basic type is the boxed cushion. Boxed cushions are made with top and bottom fabric faceplates sewn to side panels called boxing. A fabric-covered cord called “welt” is typically sewn in the seams, creating a bead effect at the cushion’s edges. The fabric cover is sewn inside out, and turned right-side out before stuffing with batting-covered foam, sized to fit. For simplicity, I am demonstrating rectangular cushions, but boxed cushions can be squares, rectangles, circles, or custom shapes. All you need to start making your own boxed cushions is a basic understanding of sewing and sewing machine functionality. For non-rectangular cushions, just throw in a little pattern-making skill, and these same techniques apply.

Getting Started

Cushion sizing. Measure your chair’s seat opening from side to side to determine the finished width (W) of your cushion, and from front to back to determine its length (L). The cushion’s finished height (H) will be a standard size equal to the thickness of the foam you order; consider comfort and aesthetics when choosing cushion height. Once you know the finished size of your cushion (H × W × L),
use the formulas in the drawing above or in the cut list (see onlineEXTRAS) to determine your part sizes.

Fabric selection. Look for fabric labeled “upholstery” or “home decor” with a 15,000 double rub count or more—although the budget-minded could go as low as 9,000 double rub count. Consider the cushion’s intended use when choosing among optional features like UV-, stain-, or water-resistance. If you choose a patterned fabric, you’ll need to order extra material to have room for pattern matching (see onlineEXTRAS).

Foam selection. Chain craft stores offer foam, but better quality materials are available from online and local foam specialists. For basic, indoor cushions, look for foam labeled high-density polyurethane.

What is welt? Welt is a decorative and structural accent made of fabric-covered cord. In boxed cushions it is added to the sewn seams to reduce the wear and tear at the edges of a cushion. Welt can be made of the same fabric as your cushion body, or choose a different fabric for a contrasting look.

Begin with the zipper panel. Cut faceplate, boxing, and zipper boxing pieces to size on the grain, and cut the welt strips—as many as needed to add up to your total welt strip length—on the bias. Sew the two zipper boxing strips together along their long side, with a 1⁄2” seam allowance. Iron this panel flat and pin the zipper to the underside of the panel. Be sure to place the zipper head down.

Sew the zipper in place. With a zipper foot installed on your machine, sew along one side of the zipper and then the other, as shown.

Rip the center seam. Flip the zipper panel over to show the outside face and carefully rip the center seam, revealing access to the zipper teeth. Check to make sure you can freely open and close the zipper.

Attach zipper panel to boxing. Cut two small scraps of fabric to act as zipper stoppers. Fold the scraps in half and pin them at each end of the zipper panel. The fold should lay about 5⁄8” from the edge as shown. Using a 1⁄2” seam allowance, stitch the short ends of the zipper panel to the short ends of the boxing strip, to create one continuous loop of boxing.

Make the welt. Pin the ends of two welt strips face to face with the free ends extending out at 90° to each other. Then pin one of these strips’ free ends to the end of a third welt strip in the same manner. Repeat until all the welt strips are pinned to create one long piece. Stitch each pinned joint at a 45° angle. Iron the seams open, and trim to 1⁄4”. Center your welt cord on the backside of the fabric, and fold the fabric strip over to encase the cord as you run it through the sewing machine. Create a 1⁄2” seam, stitching as close as possible to the cord without piercing it.

Attach welt to faceplates. For each faceplate, start by pinning the welt to one edge of the show face of the fabric, about 4” from the back corner, aligning the cut edges. When you reach a corner, snip the welt seam allowance from the edge of the fabric to just shy of the seam, allowing the cord to fold and continue along the faceplate’s next edge. Continue until you arrive back where you started. Cut your welt cord a few inches long so it overlaps its starting position. Begin sewing the welt to the faceplate, starting 2” away from the first welt end, using a welt or zipper foot.

As you approach the spot where the two welt ends meet, rip open the fabric welt seams, exposing the raw cord. Trim the cord so the two ends meet, leaving the fabric ends longer and overlapping, as shown. Then fold the fabric back down over the butted ends of the cord to finish sewing the welt to the faceplate.

Pin boxing to faceplates. With the boxing strip on top of one faceplate and show faces of the fabric facing each other, pin the center of the zipper panel edge to the center of the faceplate’s back edge. Place a pin every 3” expanding from center. When you reach each corner, snip the boxing seam allowance as shown right. Continue pinning, stopping 11⁄2” short of each end of the zipper panel. Then spin the faceplate around and pin the center of the boxing edge to the center of the faceplate’s front edge. Pin outward from center as before, until you reach the zipper. You will have more boxing than the length of the side of the faceplate. Fold the excess boxing fabric under the zipper panel ends, and finish pinning. This folded material will create neat pockets that cover the zipper ends.

Sew the final seams. With a welt (or zipper) foot still installed, stitch around all sides of the faceplate, once again keeping the seam as close to the welt cord as possible without piercing the cord. Repeat steps 7 and 8 for the second faceplate, making sure the zipper is open before finishing your stitching. Flip the cover right-side out and admire your sewing work!

Prepare the foam. Measure and cut your foam and Dacron batting (see above for sizing). Spray a light coating of fabric adhesive on one face of your foam. Align one end of your batting with the back edge of the foam face and apply light pressure to adhere. Flip the assembly over, wrapping the Dacron over the front edge of the foam, and adhere to the second face as shown.

Stuff the cushion. Unzip and open the cushion cover as wide as possible and insert foam, Dacron-wrapped end first. Incrementally shift the fabric until the foam is fully in the cover before closing the zipper and hiding the zipper head in its pocket. Then sit down and enjoy your new cushion!