Closed cell foam is made of uniform cells that maintain their shape. Because the cells have their own cell walls, they are rigid and trap a large amount of air. This makes for more sturdy insulation products.

Closed cell foam differs from open cell foam, which is made of irregularly shaped cells that are linked together. Because the cell walls are broken, the foam is softer, making great sound dampening products, furniture, and sponges.

Most insulation products used in remodeling and construction are closed cell, because they trap air for greater insulation value, and do not easily absorb moisture