Window bench - naked no more!

Supplies:

• 3” high density foam
• batting (the batting I used was thick)
• fabric
• thread to match fabric
• cord for piping
• long zipper (I’ve seen velcro used on other blogs if you can't get a long enough zipper)

Measurements of the front, back and sides of my foam:

• Front: 102.25”
• Side 1: 31.5”
• Side 2: 32”
  *our window bench is not a perfect trapezoid, hence the size differences b/t the two sides (see below drawing)
• Back: 56.25”

Cuts for front, back and side strips and piping:

*For the front and sides, I added 1.5" to the height of the foam to allow for seam allowance and room for the batting and 2" to length.

• Piping: two 2” strips, 223” long each
• Front: 4.5” x 104.25”
• Side 1: 4.5” x 33.5” 
• Side 2: 4.5” x 34” 

• Back: 5.5” x 58.25” (this is 5.5 instead of 4.5 b/c you have to insert a zipper)

*I did not include measurements of top and bottom (big pieces) above because I just laid the foam on the fabric and traced out .75” to get the measurements for those pieces

I combined steps from these two blog posts to make my cushion - both have lots of good pics that will likely help you out: Pretty Hand Girl and Sophisticated Yellow.

Steps

1. Cut foam to size with an electric carving knife or get it cut for you. I (by that I mean Michael) made a template out of newspaper and took it to Burgess Supply to get them to cut it for us. The window bench is so large they actually had to glue two pieces together. You can also find foam at JoAnn’s Fabric. The longest foam I could find was online at the Foam Factory but since I found a local place that could cut it for me, I just went for that.
2. Wrap foam in batting. Hand stitch batting together where it overlaps to keep it together (preferable to use a sturdy thread, though I didn’t b/c I didn’t have any).
   
3. Place foam on fabric. Mark lines .75” out, all the way around the foam and connect lines using a ruler. Repeat for bottom piece. Our window bench is not a perfect trapezoid, so I flipped the foam to trace out the bottom piece. If I hadn’t done this, the two pieces wouldn’t fit together correctly. If you have a perfectly rectangular window bench, you can just fold the fabric, trace and cut both the top and bottom at once. This is what most blogs I read recommended.
   
4. Mark lines for all 4 side pieces and piping. I marked everything I would be cutting first because I was close on fabric and wanted to make sure I had enough. Be forewarned, you need a lot of piping!
   
   
   
5. Cut all pieces.
6. Make piping. You do not need to cut the pieces on the bias, which makes it quicker. See some photos here if you’ve never made piping before - start at step 10 once you’ve stitched enough fabric together for your total length (this post is for cutting on the bias, but gives you visuals on how to sew piping in general).
7. Attach piping to top piece. Lay piping on top of fabric, with raw edges together and pin in place. Sew together using zipper foot. When you reach the corners, make several cuts in the piping to allow it to turn more easily. See visuals here for this step and for joining the ends of the piping together if needed (steps 8 and 10).
   
8. Insert zipper into back piece (I followed the directions of this blog post if you want visuals). Note: most blogs use velcro, rather than a zipper, I’m assuming b/c long zippers are hard to find. I cut a piece of zipper 58” from a zipper roll my mother in-law had. I then pressed the back piece in half with an iron and then cut it down the middle. I then zig-zag stitched both long edges that I just cut so they wouldn’t fray (not sure if this is necessary, but I read you should do that). Sew the two pieces together w/ a ½” seam allowance using your longest stitch width (you will take this stitch out once the zipper is in). Open and press ½” sides down w/ an iron. Pin (or tape) zipper in place. Sew using zipper foot. Take out your initial seam to expose zipper. I then sewed across the zipper 2” down from either side using a wide zig-zag stitch and seam length of 0 to close the zipper off (since i just cut it from a roll, it didn’t have an official start or stop place).
   
9. Join side pieces. Pin the side pieces, together, right-sides facing each-other around your foam. One blog I read just used a ½” seam allowance instead of pinning them together, but the way I cut the strips, I needed to pin the pieces to make sure I had the right fit (I had more than ½” leftover on most sides). Sew together where the pins are (I actually marked a line w/ a ruler and fabric marker to make it easier to sew straight).
   Note: I had the top piece on the foam in this pic, but you don't have to have it there for any reason when you're pinning together the sides.
   
10. Lay top fabric piece on top of foam. Pin side pieces to the top (line up raw edges and face the right sides of the fabric together). Stitch with zipper foot as close to the piping as possible (you can't see the piping during this step, but can feel it).
    
    
11. Flip fabric right side out and put on your foam if you want to test out the fit.
     
    12. Open zipper. Pin bottom piece to sides, lining up rough edges (right sides will all be facing in). Sew again with zipper foot, as close to piping as possible.
     
    

    13. Flip right-side out, stuff (carefully so you don't rip a seam like I did). Done at last!