How to Make Custom Foam Cushions

November 5, 2025

Creating custom foam cushions for your chairs, sofas, or benches is an amazing way to make sure perfect comfort, fit, and longevity. Whether you’re restoring an upholstered piece, building a new one, or simply replacing tired seat pads, getting the foam right is essential.

This guide walks you through everything from choosing the correct foam type to measuring, cutting, layering, and finishing for great results.

Making Custom Foam Cushions

While fabric and frame often get the most attention in upholstery projects, the foam inside plays a prominent role in comfort and durability.

Custom foam cushions allow you to:

  • Match the exact dimensions of the seat or back of the furniture.
  • Choose the right firmness, layer thicknesses, and support type for the user and piece.
  • Replace worn foam, too often the culprit behind sagging, uneven seats, or poor support.

Materials & Tools You’ll Need

Following is a checklist of essential materials and tools you’ll need on hand:

  1. Upholstery foam sheets (varying densities)
  2. Electric kitchen knife or hot wire foam cutter
  3. Measuring tape, ruler, marker
  4. Batting (fiber wrap), if required for finishing softness
  5. Spray adhesive (foam‑to‑foam if layering)
  6. Cover fabric/cushion cover (optional)
  7. Stapler or upholstery tack gun (if incorporating into furniture)
  8. Utility knife or sharp foam‑cutting blade
  9. Clean and flat work surface

Step by Step Guide to Make Foam Cushions

1. Measure Your Seat

Measure the width, depth and thickness of the existing cushion or seat base. Note any unusual shapes (curves, bevels) or desired height changes. Keep a small allowance (e.g., 7‑10 mm) if you’re inserting into a cover or if you want a cozy fit.

2. Choose the Right Foam Type & Firmness

Select your base foam according to usage:

  • High‑density foam for frequent use and long life
  • Medium to soft density if you want a more relaxed “sink‑in” feel
  • Outdoor cushions may need special foam (e.g., rapid‑dry or water‑resistant)

3. Cut the Foam to Size

Mark the dimensions on the foam sheet. Using an electric kitchen knife, hot wire cutter or sharp utility blade, carefully cut the foam. Keep cuts straight and edges clean. If you’re layering foam (e.g., firmer base + softer top layer), cut each layer individually.

4. Glue or Bond Layers (If Required)

If you’re want to create a multi layer cushion (for example, a firm base with a softer mattress layer on top), apply spray adhesive to the bond surfaces and press together firmly until it gets set.

5. Wrap in Batting

Wrapping the foam in a layer of polyester batting will soften the edges, smooth the transition between foam and cover, and improve final appearance. It also helps the fabric look evenly.

6. Insert Into Cover or Re‑assemble Seat

Place your newly cut and wrapped foam into the cushion cover or seat frame. Ensure it sits flush, the fabric or upholstery work can proceed, and seat edges are clean and defined.

7. Test for Comfort & Finish

Sit on the cushion or place the restored seat in position. Check for even support, no sagging or hollow spots, and correct height. If needed, adjust thickness by trimming or adding another layer of foam or batting.

Common Mistakes to Avoid

  • Cutting foam too small results in sagging or shifting foam.
  • Using a low‑density foam for heavy use, which can flatten rapidly.
  • Skipping the batting layer causes fabric to show foam shape or seams.
  • Inaccurate measurement leads to loose fit or bulges in covers.
  • Neglecting to measure height or thickness affects comfort and appearance.

Final Thoughts

Furniture comfort starts from the inside out and nothing influences that like the foam under your fabric. By measuring accurately, selecting the right materials, and cutting intelligently, you end up with a finished piece that fits perfectly, supports properly and lasts much longer. Use the guidance above and the right tools from JA Milton to make your next cushion project a standout success

Shop JA Milton Today

At JA Milton Upholstery, we offer an extensive selection of upholstery foams, batting, adhesives and cutting tools, everything you need to build custom cushions correctly. Whether you’re a professional upholsterer or a DIY enthusiast, we support your project at every step with quality materials and expert advice.

Visit us at JA Milton to explore our foam range and accessory supplies.

Bring your seating back to life with custom‑cut foam cushions that look great and feel amazing.

SHOP NOW


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