How to Upholster a Foam Cushion

upholstered bench

The Spruce / Debbie Colgrove

Overview
  • Total Time: 3 hrs
  • Skill Level: Intermediate
  • Estimated Cost: $40

A bench is a handy piece of low-profile furniture if you need a quick place to sit or extra seating when guests come over. But benches often have hard wooden seats that aren't very comfortable. That's why many DIYers turn to making their own custom upholstered foam cushions. This project requires intermediate sewing skills and a few hours of your time. Plus, unlike with store-bought cushions, you can pick fabric that matches your decor style and create exactly the size of cushion you need. You can even make upholstered foam cushions for chairs, chests, and other similar furniture pieces.

What You'll Need

Equipment / Tools

  • Measuring tape
  • Marker
  • Electric knife
  • Scrap of cardboard or wood
  • Scissors
  • Pins
  • Iron and ironing board
  • Sewing machine

Materials

  • Foam (in your choice of thickness)
  • Fabric
  • Matching thread
  • Cording

Instructions

  1. Cut the Foam to Size

    Cutting a piece of thick foam can be a challenge. Scissors or a craft knife often can leave you with an uneven edge. An electric knife will get you the best results.

    Measure and mark the foam to be the same size as your bench top. A rotary ruler can help assure that you are marking straight lines. Then, cut the foam with your electric knife.

    If you've never cut with an electric knife before, practice on a scrap piece of foam. Also, protect the surface under the foam with a scrap of cardboard or a piece of wood, so you don't damage your work station

    cutting foam
    The Spruce / Debbie Colgrove
  2. Calculate Your Fabric Needs and Cut the Fabric

    For this project, we'll use a 1/2-inch seam allowance.

    Cut the fabric to the length of the cushion plus 1 inch and the width of the cushion plus 1 inch. You'll need two pieces like this: one for the bottom and one for the top of the cushion.

    Then, cut the side panel. Its width should be the thickness of the foam plus 1 inch, and its length should be the distance around the cushion plus 1 inch. If the distance around the cushion is longer than your fabric, you'll need to seam the sides. Make calculations, so your seam will be at a corner if possible. And remember to add 1 inch to the length for each seam you have to create.

    Next, cut the ties, which you'll ultimately place in each corner of the cushion to secure it to the bench. Measure from the cushion bottom to the bench legs (or wherever you plan to tie the cushion), and add enough length to be able to tie a bow or knot. It can be helpful to mark a piece of ribbon to gauge how long you'll need to make the ties and then measure the ribbon. Cut four 1-inch wide strips in the measurement you've calculated plus 1 inch. (You can always make more ties if your furniture is especially large or you want the cushion to be extra secure.)

    For reference, in this example the bench is 11 inches wide by 64 inches long, and the foam is 4 inches thick.

    • The top and bottom pieces of fabric are 12 inches by 65 inches.
    • The side piece is 5 inches by 151 inches.
    • Another option for the sides (shown in the diagram below) is to use two pieces that are 12 inches by 5 inches for the short sides and two pieces that are 65 inches by 5 inches for the long sides.
    • The four ties are 1 inch wide and 26 inches long.
    An example of how to calculate how much fabric you will need to sew a cushion cover
    The Spruce / Debbie Colgrove
  3. Create and Place the Ties

    Fold one end of a tie in by 1/4 inch to enclose the raw edge. It can be helpful to use an iron or pins, depending on what kind of fabric you're using. Then, fold the strip in half lengthwise, and press the fold.

    Open the folded strip, and bring the raw edges ​to the center fold. Press well. Then, with the strip folded in half lengthwise again, sew along the edge to hold all of the folds closed. Press again. The tie should now be 1/4 wide. Repeat this for all of the ties you're making.

    Mark the fabric for the bottom of the cushion where you're going to place the ties. Pin the end of the tie that is not turned under to a bottom marking. Align the end of the strip and the edge of the fabric, so the end of the tie will be in the seam allowance. Then, baste the tie in place. Repeat this for all of the ties.

    Finally, bring the ends of the ties together on the center of the bottom fabric. Tie and pin them in place, so they won't be caught in your other sewing.

    Controling the ties so they don't get caught in your sewing.
    The Spruce / Debbie Colgrove
  4. Apply the Trim and Sew the Side Sections to the Top

    Sew on the trim to the sides, so it will meet with the seam allowance of your fabric. 

    If you're using one continuous piece for the sides: 

    • Place the ends of the piece right sides together, making sure there are no twists in the fabric.
    • Fold the top length in half to find the center. Mark the center.
    • Place the seam of the side sections at the half mark.
    • Match the edges, and pin the side section to the top section of the cushion.
    • Sew the sections together using a 1/2-inch seam allowance, pivoting at the corners.
    • Apply a seam finish.

    If you're using multiple pieces for the sides:

    • Place each end of the front section even with one end of a side section.
    • Join the ends right sides together, using a 1/2-inch seam allowance.
    • Repeat to add the back section to the other ends of the side sections.
    • Match the seams to the corners of the top section of the cushion.
    • Align the edges of the side sections and top section. Pin in place.
    • Sew the pieces together, using a 1/2-inch seam allowance and pivoting at the corners.
    Sewing the sides on a cushion cover.
    The Spruce / Debbie Colgrove
  5. Attach the Bottom and Finish the Cushion

    Mark the center back of the bottom section. Then, mark an equal distance from the center for a space that will be large enough to fit the foam inside the cover. You won't sew that space yet.

    Sew around the bottom section to attach the sides with right sides together, using a 1/2-inch seam allowance and pivoting at the corners. Apply a seam finish (such as a zigzag stitch) to all of the seam allowances.

    Turn the cover right side out, and press it.

    Then, gently guide the foam through the open space you left, making sure the cushion reaches into all four corners. 

    Once the foam is inside the cover and everything is smooth, pin the opening closed and hand sew it. Use a slip stitch to have the stitching as invisible as possible.

    Leaving an opeing to turn the cover right side out saves you using the seam ripper.
    The Spruce / Debbie Colgrove