A burial vault is a lined and sealed outer receptacle that houses the casket and protects it from the weight of the earth and heavy maintenance equipment that may pass over the grave. Because a burial vault is water-resistant, it also helps preserve the beauty of the cemetery by preventing the ground from settling.
Urns that will be buried in the ground are required to be placed in an urn vault. A lined urn vault is made of high-strength concrete and reinforced with durable plastic or a combination of durable plastic and metal.