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How to Make a Boxed Edge Bench Cushion Using Upholstery Fabric and Poly-Foam

Loretta learned to sew on her grandma's treadle sewing machine. She began sewing her own clothes in 7th grade and still enjoys fabric work.

Wood bench with new cushion made with upholstery fabric and poly-foam

Wood bench with new cushion made with upholstery fabric and poly-foam

Create a Furniture Cushion for Comfort or Scratch Protection

You may wish you had a comfortable cushion for a hard bench or to prevent scratches from clothing or pets. It's easy to make one to suit your needs.

Note: Please be sure to view each thumbnail. Additional instructions are within the photos.

Project Overview

Here is the overview of the project. Details follow in other sections.

Measure for Finished Size and Side Seams

Measure for the finished dimensions of your cushion. It is important to decide on the side seams before cutting your fabric. The simplest and easiest is the "knife edge." This style is two pieces of fabric with a single seam all around, leaving an opening with a zipper or velcro. You can sew piping or cording in the seam to dress it up a bit. Be sure to account for the knife edge fabric that will accommodate your foam or polyfill.

"Boxed Edge" Style

I chose a "boxed edge" for my cushion. This style is constructed with a vertical sidewall that is the same height as the thickness of the cushion foam, 2 inches in my case. Assemble the top and bottom sections to the sidewall fabric to form a box. I created my bottom piece out of two hemmed sections that overlap to create the opening. As an example, pillow shams are often constructed this way.

Serge or Sew: Seam Allowance

Determine whether you will serge using 1/4" seams or sew using either 1/2" or 5/8" seams. Add this seam allowance to your finished dimensions for the top, bottom, and sidewall if used.

The Finished Project

My finished cushion would be 18" by 36" using a seam allowance of 1/2". This added 1 inch to my dimensions to become 19" by 37". For my sidewall to end up at 2", and having a 1/2" seam, I needed a 3" strip long enough to go past the perimeter by a few inches. 112" in my case. Measure twice, cut once!

Step 3. Cut Pieces to Size and Stabilize Edges if Needed

I first cut my "sidewall" strip. I measured my three-inch width, cut a little way, and then continued cutting by folding my three-inch strip over itself. That way, I did not have to use the tape measure constantly; I just followed the edge until I had a long strip. As it turns out, I needed to join two strips to get my full 112 inches. Fold 1 1/2" to 2" at one end and stitch in place with a sewing machine. This creates the finished edge when the pieces are joined.

Next, I cut my single top piece 19" x 37". Then I cut two pieces to make the bottom of the cushion. I wanted the two pieces to overlap and create a hemmed opening for the foam to be inserted. I cut mine 19" by 24" and turned the 1" hem twice, so there were no raw edges. You may choose to have a zipper or velcro, so measure and cut accordingly.

To prevent raveling, I serged around all the edges of my pieces. You may need to do a zigzag stitch if you do not have a serger. If your fabric does not fray, you can skip this step.

Step 5. Sew the Sidewall to the Top Piece

Match up any pattern that your fabric may have. Mine has somewhat of a diamond pattern that I wanted to continue down the front of the cushion. Clip or pin in place, right sides together.

Scroll to Continue

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Using this match-up as a guide, fix the sidewall in place to begin the attachment from the folded edge of the sidewall. Follow around the entire perimeter. Please see the thumbnail photos, and it will make sense.

At this point, I used a sewing machine, not my serger. Begin sewing from the folded edge of the sidewall to the top piece. Continue to the corners, pivot, and continue sewing. Sew a little overlap from where you started, and trim the sidewall if you cut it too long. Better too long than too short.

Step 7. Prepare the Bottom and Sew to Sidewall

Along the width, hem one edge of each of the two pieces, which comprise the bottom of the cushion. When overlapped, this will create the opening to turn the fabric's right sides out and insert the foam.

Baste the overlap to prevent shifting while sewing to the sidewall.

Having right sides in, sew the complete perimeter of the bottom structure to the perimeter of the sidewall. Pivot at corners. Trim corner bulk if needed.

An Overview of the Project

Here is the top, bottom, and the 3" strip that has become the 2" sidewall of the cushion. You can detect the sham style hemmed opening on the bottom piece.

Here is the top, bottom, and the 3" strip that has become the 2" sidewall of the cushion. You can detect the sham style hemmed opening on the bottom piece.

The Finished Exterior

Here is the top, bottom, and the 3" strip that has become the 2" sidewall of the cushion. You can detect the sham style hemmed opening on the bottom piece.

Step 8. Prepare and Cut the Poly Foam

You may want a second opinion as to the comfort of your poly foam. I always prefer puppy-approved components.

I used this foam for my cushion. You may want a thicker piece, but this was right for us. The length is easy to cut with an electric knife, and you will have foam left over for pillows or another project. Measure for your finished cushion. Measure twice. Cut once. An electric kitchen knife cuts through this foam like buttah (New York accent).

(This is longer than needed for this project, but unless you get a custom cut, this may be the cheaper option. You will also have leftovers for pillows or other projects).

Step 10. Insert the Foam into the Cushion

This foam can be easily squished or folded into a shape you need. Use the opening on the bottom that was created from the two hemmed pieces. This is very similar to pushing a pillow into a sham. Tug and pull until it fits properly and the corners are in place.

Enjoy Your New Cushion!


This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 The Sampsons