Diamond Stitching: How to Sew a Diamond Quilted Cushion

Item # X-HT-300602

Dress up a cushion cover and add some style and interest with diamond quilting. What are diamond quilts? It’s a technique of sewing crisscross stitch lines to form diamond shapes in a piece of fabric. It’s an easy way to take a plain cushion or upholstery piece to the next level. It may look complicated, but if you can sew a straight line you can add diamond stitching — also known as diamond pleating — to your next cushion project. In today’s video, we’re making diamond quilted cushions for the dinette seating area in an RV. Let’s get started.

Learn how to sew a seating cushion with decorative diamond quilting.

Here's our finished quilted cushion along with the two types of foam needed for this DIY.

Diamond pleating is most often seen in vinyl and leather upholstery. For our RV cushion, we’re using beautiful EverSoft™ Indoor/Outdoor Vinyl Fabric. EverSoft is a great choice for RV seating, as well as cushions and upholstery on your boat, patio and in your home. The vinyl fabric adds a high-end, leatherlike look to your application while remaining mold and mildew resistant and easy to care for. The fabric’s unique four-way stretch properties make it incredibly easy to contour and shape during upholstery work.

At Sailrite®, we take the intimidation out of DIY. Our Fabric Calculator calculates how much fabric, foam and zipper chain you need, as well as the other materials you need to make your cushion. The calculator renders the dimensions of your cushion panels and even adds seam allowances for you. It’s an incredibly useful tool that’s available for free on the Sailrite website.

Watch the video below to learn how to sew a cushion with beautiful, professional-looking diamond quilting.

We hope you enjoyed this cushion tutorial video. We’ve got lots of tutorials on how to sew cushions for your boat, patio, home and more. Interested in an easy, 30-minute cushion project? Check out our blog “How to Make a 30-Minute Box Corner Cushion” (#300459XHT). The box corner technique makes it very easy to sew a cushion — even if you’re a beginner.

You should also explore the other videos in our RV Renovation Series. We’re renovating an RV from top to bottom, inside and out. You don’t want to miss any of the exciting projects in this series. The “before and afters” are truly incredible!

Video Chapters:

  • Intro — 0:00 min.
  • Measuring for Cushion — 1:14 min.
  • Cutting Foam to Size — 4:59 min.
  • Discussion of Foam Density — 7:21 min.
  • Cutting Plates — 12:11 min.
  • Measuring & Cutting Boxing — 15:14 min.
  • Creating Zipper Plaque Boxing — 18:20 min.
  • Quilting Diamonds in Top Plate — 25:36 min.
  • Creating Match-Up Marks — 41:39 min.
  • Sewing Zipper Plaque to Boxing — 43:22 min.
  • Sewing Boxing to Top Plate — 46:26 min.
  • Transferring Match-Up Marks to Boxing — 56:39 min.
  • Sewing Bottom Plate to Assembly — 58:34 min.
  • Inserting Foam — 1:04:01 min.
  • Materials & Tools List — 1:08:53 min.

Materials List:

  • High Density Polyurethane Foam (Medium) 5" x 24" x 80" #285M2480
  • Cushion Underlining Black 54" Fabric #772100
  • EverSoft™ Indoor/Outdoor Navy 54" Vinyl Fabric #122214
  • Seamstick 1/4" Basting Tape for Canvas & Upholstery (36 yds.) #122065
  • YKK® Continuous Zipper Chain #5 Black (Coil Chain) #104444
  • Thread from Sailrite - we used V-92 Polyester
  • YKK® Zipper Slider #5 Black Metal Single N/L Pull Tab (Coil Chain) #122251
  • Fabric Backed 1/4" Sew Foam 58" (5 yds.) #121506-5
  • 3M™ General Trim Spray Adhesive 18.1 oz. #73211
  • Cushion Wrap Silk Film 54" (10 yds.) #103933

Tools List:

  • Sailrite® Blade Foam Saw V2 with Carrying Case (110V) #121244
  • Scribe-All® Water Soluble White Marking Pencil #120681
  • Gingher® 8" Scissors Right Handed #19104
  • Deluxe Tape Measure 120" #123120
  • Clear Acrylic Ruler 6" x 24" #102400
  • Sailrite® Ultrafeed® LSZ-1 PREMIUM Sewing Machine With WorkerB® Power Pack (110V) #311603
  • Sailrite® Ultrafeed® Industrial Sewing Table #120934
  • Deluxe 5-1/2" Magnetic Sewing Guide #103597
  • Chalk Pen White #123131
  • Ergonomic Thread Snips #102991
  • Tape Measure, Marker, L Square, Straight Edge, Stapler, Shop Vac