Build Your Own Mattress — Any Shape & Size!

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Do you have an irregularly shaped sleeping area and need a custom mattress design? You’re in luck! Today’s DIY project is for you. Some boat sleeping berths or camper sleeping quarters have angled walls that require a unique mattress shape. Even if your bed frame or sleeping area is a standard shape, making a custom mattress can save you money and allow you to create the perfect mattress thickness and firmness level for your support and comfort. Let’s get started with this easy custom mattress build.

Video Chapters:

Cutting Foam to Size — 00:22 min.
Cutting Out Fabric — 1:30 min.
Tacking Stitch — 4:54 min.
Creating Zipper Plaque — 5:32 min.
Sewing Boxing to Top Plate — 11:12 min.
Sewing Bottom Plate to Assembly — 16:07 min.
Inserting Foam — 22:14 min.

Materials List:

Sailrite® CushionRite® Premium Foam
CushionRite® Foam & Fabric Spray Adhesive 16.9 oz. #125476
CushionRite® Foam Mattress Protector White 106" Quilted Fabric #126854
Seamstick 1/4" Basting Tape for Canvas & Upholstery (36 yds.) #122065
Tex 70 (V-69) White Bonded Nylon Thread 4 oz. (1,500 yds.) #124935
Lenzip® #2 White Continuous Coil Zipper Chain #126079
Lenzip® #2 White Style A Single Locking Metal Zipper Pull (Coil Chain) #126084
Template Plastic Plain A4 (2 pack) #123106

Tools List:

Sailrite® Blade Foam Saw V2 with Carrying Case (110V) #121244
Tape Measure 120" #102986
Kai Stainless Steel Bent Handle 9" Scissors #125661
Sailrite® Clear Acrylic Ruler 6" x 24" #102400
Sailrite® Deluxe Fabricator® Sewing Machine Package (110V) #400600
Sailrite® Zipper Jig #121976
Large Fabric/Leather Grip Clips #126365
Pencil

The first thing to ask yourself is: “What kind of foam do I need?” We recommend Sailrite® CushionRite® Premium foam for mattresses. CushionRite Premium is high-density polyurethane foam. Its density rating of 2.8 pounds per cubic foot means it will provide excellent support while still delivering on comfort, making it ideal for high-traffic applications, like mattresses, that receive daily use. And best of all, CushionRite Premium lasts up to 12 years and is made in the United States!

Now that you have your foam type determined, it’s time to talk about foam firmness. Firmness is not the same as density. Firmness, known as Indentation Force Deflection (IFD), is how soft or firm the foam feels. You can have a high-density foam with a soft firmness and a high-density foam with an extra-firm firmness.

Let’s use our project mattress as an example. We glued three layers of CushionRite Premium Foam to create our mattress. The bottom and middle layers are Premium Firm and the top layer is Premium Soft. This gives our mattress the support we’re looking for, and the Soft top layer adds comfort and cushion.

An important tip: When layering foam, start with a firmer foam on the bottom (higher IFD) for support, then add a softer foam on top (lower IFD) for comfort. Think of the base foam as a box spring — it stabilizes the cushion even if the top layer compresses over time.

We hope you enjoyed today’s DIY mattress tutorial. If you have questions, feel free to leave a comment below. If you’re looking for more helpful tutorials, click here to browse hundreds of free DIY projects!