Learn How to Sew a Box-Edge Cushion in 5 Easy Steps

Custom cushions can be pricey, but this DIY cushion project will have you sitting pretty and saving money.

blue window seat cushion underneath window

Turn an ordinary bench or window seat into a comfortable resting spot with a professional-looking box-edge cushion. A box-edge cushion has a wide panel (called a gusset) between the top and bottom of the cushion to accommodate a piece of foam, which results in a thick, comfy, and tailored cushion. It is a versatile design that can be used for both seat cushions and against a backrest.

The instructions below are for an 18x24x6-inch cushion, but you can adjust the measurements for custom window seat cushions or bench seat cushions.

What You'll Need:

  • 1 yard of decorator fabric (52/54-inches wide)
  • 1-1/4 yards of fleece
  • 1-1/4 yards of extra-loft batting
  • 1 17x23x5-inch piece of high-density foam
  • Upholstery or carpet thread
  • Heavy-duty spray adhesive
  • Hand-sewing needle and buttons

Quantities specified are for 52/54-inch-wide decorator fabrics. All measurements include 1/2" seam allowances unless otherwise noted. Sew with right sides together unless otherwise stated.

Step 1: Cut the Materials

To make the best use of your fabrics, cut the pieces in the order that follows.

Step 2: Prepare the Foam and Fabric

Use heavy-duty spray adhesive to glue the extra-loft batting to the corresponding sides of each high-density foam piece. Line each decorator fabric piece with corresponding fleece piece; baste each pair together.

Step 3: Assemble the Cushion

Sew the fleece-lined gusset rectangle to the cushion top rectangle; clip the corners as necessary and turn under the raw ends. Repeat by sewing the opposite edge of the gusset rectangle to the cushion bottom rectangle. Leave a large opening; turn to the right side.

Insert the batting-covered foam shape into the cushion cover. Hand-sew the opening closed.

Step 4: Finish the Corners

Give each corner of your box-edge cushion a little extra polish by adding a seam. Along each side seam, flatten the edge by pushing the batting-covered foam shape away from the seam; pin, like you are making a hem. Using a long running stitch and upholstery or carpet thread, tuft the edge through both adjacent sides.

Step 5: Tuft the Cushion

Using a fabric pen, make matching marks for the placement of four buttons on both sides of the cushion. Using upholstery thread and a needle, hand-sew the buttons onto the cushion.

Now that you’ve learned how to make your own cushions, give these upholstery projects a go.

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