What is the purpose of the vault or outside container?
There are several kinds of outside containers that may be used to hold the casket. The type known as a vault may be made of concrete or metal, and some recently have been made of fiberglass. Vaults not only prevent crushing of the casket by the earth load, but may be sealed to inhibit the entrance of water into the vault and casket. The other type of outside container is commonly called a rough box, or concrete outer container. Its only function is to prevent the crushing of the casket by the earth load, which results in the sunken grave in the cemetery. It does not attempt to seal out water or moisture, and is generally less expensive than the vault. Many cemeteries prohibit the use of wooden boxes as outside containers because they deteriorate. This causes the grave site to settle, increasing the maintenance cost to fill in sunken graves.