How to begin your product selection for replacing the foam in your upholstered furniture
To get the support and feel you want, you will first need to determine the density of foam needed. This is expressed by the first two numbers. For good support and longevity in seating foam, or thinner back foam applications, we always recommend then 2.7 - 2.8lb high density foam. Lower density foam will work well for most back cushions, and softer effects can be achieved.
Next, determine the firmness of the foam you want ILD or compression). This is expressed in the last two numbers. The higher the number, the more firm the foam. These numbers are rated for performance at 4 inches of thickness with an average weight of 165lbs. For best performance we recommend Medium Soft foam (F2735) for applications over 4", Firm foam (F2845) and extra firm foam (F2860) are preferred for applications less than 2" thick, or at any thickness to support higher weights.The firmness (ILD) will feel softer under 4" and firmer over 4". You may want to adjust these numbers based on the thickness of your piece and the weight to be supported.