What is commonly used to provide structural integrity and protection for a casket?

A concrete vault is commonly used to provide structural integrity and protection for a casket. Its primary purpose is to support the weight of the earth above it and prevent external elements from damaging the casket over time. Concrete vaults are designed to be durable and resistant to natural wear, such as water damage, soil movement, and pests. By encasing the casket, a concrete vault helps to maintain the casket's condition and aids in the preservation of the remains it holds.

Other materials, such as wooden boards or steel frames, may be found in various types of casket construction or design, but they do not serve primarily as protective barriers in the burial scenario. A grave liner, while providing a certain level of protection, typically does not offer the same structural integrity as a concrete vault; it is usually lighter and less robust. Thus, the most effective choice for ensuring the long-term preservation and stability of a casket is a concrete vault.