Have you ever wondered what goes inside your sofa seat cushions to make them so comfortable to stretch out and relax on? While a variety of materials may fill furniture around the world, the most common seat stuffing is composed of polyurethane foam. The standard of foam is measured in grades based on its compression and density and it also is held to a separate measurement for how many years it is expected to last.
The compression of sofa foam is measured by how many pounds of pressure it takes to compress the material down to 3/4 of its initial bulk per cubic foot, also called its indentation load deflection (ILD). An average ILD for the bottom cushions of a couch would be in the low 30’s. Density is the weight and amount of foam that takes up the space of that cubic foot. According to The Foam Factory low density means less material with more air in the foam and would create an ideal softness for a back cushion.
Over time this material can degrade and the seats lose their wonderful bounce and end up looking like a deflated old balloon. This is because the polyurethane slowly disintegrates over time and generally the lower the grade of foam, the quicker that this will happen. The good news is that it is actually possible to purchase a sofa foam replacement for a sad looking cushion and restore it to a luxurious plumpness.