upholstery foam support factor
What Is Upholstery Foam Support Factor?
The upholstery foam support factor tells you how well a cushion resists bottoming out once you sit down. Also called the sag factor or comfort factor, it compares the force needed to compress foam to 65% versus 25% of its thickness, measured as IFD (indentation force deflection). A higher ratio means the foam feels soft on the surface yet firms up underneath to hold your weight.
Why It Matters for Your Cushions
- Comfort: A good support factor delivers that sink-in-then-supported feel on sofa seats and dining chairs.
- Durability: Foam with better support, usually paired with higher foam density, tends to hold its shape longer.
- Fit for purpose: Seat cushion foam needs more support than back pillows or decorative pads.
What to Look For
Weigh support factor alongside foam density and firmness. High-resilience foam typically offers a higher support factor than standard polyurethane, making it a strong choice for everyday seating. Wrapping foam in polyester batting softens the edges and helps your upholstery fabric fit smoothly.
Ready to rebuild your seating? Browse the upholstery foam and cushion supplies below to find the right support for your next project.
