An elastic material deforms in proportion to the applied load: greater loads result in predictably greater deformations and vice versa. If time is a factor in the load versus deformation characteristic, then the response is considered to be viscoelastic, which will be discussed separately. The response of support surfaces made from resilient foam is predominately elastic. Foam support surface products are made from two basic types of foam - open cell or closed cell. Foam is said to have "memory" because of its tendency to return to its nominal shape or thickness. Bryant suggests that the minimum density or weight per cubic foot of the bed support surface material should be 1.3 to 1.6 pounds and convoluted foam should have a minimum of 4 inches from the bottom of the foam to the lowest point of the convolution to achieve the optimal pressure reducing effects of the material.

Foam products frequently consist of foam layers of varying densities or combinations of gel and foam. Other products have a series of air-filled chambers covered with a foam structure or are available as multi-density closed cell products, 4-10 inches deep with deflectable tips. For these types of products, "memory" is not total because only the foam components will return to their unloaded shape. Several seat cushion products have this construction. The advantage of support surfaces with a combination of fluid-filled bladders and resilient foam would be to provide a degree of postural stability with a resilient shell and improved envelopment with a fluid or viscous fluid-filled layer at the interface.