Cemeteries may require a concrete vault as a minimum requirement. Families may choose a vault if they want to have a container that is designed to also keep out outside elements.
Outside containers are not required by law. They are an individual cemetery requirement. The reason cemeteries require some type of outside container is for maintenance purposes. If something that is structurally sound is not placed around the casket then, over time, the weight of the earth placed on top of the casket will eventually damage it and the cemetery will have to continually fill in graves.
Here is a selection of vaults we have available.