Do you need a vault to bury an urn?

The purpose of a vault is to enclose and protect the casket or urn and prevent the ground from caving in over time. Some cemeteries require that you use a burial vault when burying an urn. Generally, the vault is made of concrete, but more cost-effective options like plastic vaults perform the same function.

A burial vault is essentially used to protect the urn. It is made from a hard substance and prevents the ground from caving in on the urn due to underground forces. Should you choose to memorialize your grandad's life with burial, the cemetery will likely require you to make use of a burial vault.