There are a lot of buzz words thrown around when talking about foam so we wanted to break down what it all means. Foam is often referenced with two numbers, such as 1545. The first two numbers represent the foam density and the second two numbers represent the indentation load deflection, more commonly known as ILD.
When we are talking about density we are referring to how much material is actually being used in a standard unit of foam. A lower density foam would lose its shape faster as there is less material in the same space.
Foam comes in a wide range of density used for a variety of purposes. A lower density foam would be used in packaging or a camping cot. Higher density foam would be used in commercial seating or in a boat or high-end residential furniture. There is a correlation between foam density and longevity of the foam. Not surprisingly, there is also a cost correlation. Longer lasting foam costs more money. The foam density most commonly used for mid-level residential furniture is 1.8. When foam is being used for mattresses or a family sofa that is sat on for hours a day, then higher foam density matters more than with your play couch which typically will have a lot less concentrated use and will therefore last longer as well.
Indentation Load Deflection (ILD)
This number refers to how many pounds of pressure is needed to compress one 4 inch thick 15 inch x 15 inch piece of foam by 25%. So an ILD of 60 pounds means 60 pounds was needed to compress the square of foam.
A higher ILD is indicative of a firm foam and a lower ILD would refer to a soft foam. Generally play couches need relatively firm foam in order for builds to stay in place. Softer foam may be more comfortable for relaxing but will not hold as much weight during play.